Hello everybody,
I am been able to configure almost everything in SDLmame assignement except the Covers artwork, even if I explicitely declare the Covers path to the zip archive containing the scans they are not shown in the Cover tab of the embedded UI, of course I am talking about of existent cover archives like the N64, SNES and Genesis games. Following are my INI settings for MESS and UI, am I missing something?

mess.ini

Code
#
# CORE CONFIGURATION OPTIONS
#
readconfig                1
writeconfig               0

#
# CORE SEARCH PATH OPTIONS
#
homepath                  .
rompath                   /Volumes/Archivio_HD/Archivio_ROMs/MAME_MESS/0215_ROMs;/Volumes/Archivio_HD/Archivio_ROMs/MAME_MESS/0215_SL_ROMs
hashpath                  /Applications/Emulatori/SDL_MESS/hash
samplepath                /Volumes/Archivio_HD/Archivio_ROMs/MAME_MESS/0215_EXTRAs/samples
artpath                   /Volumes/Archivio_HD/Archivio_ROMs/MAME_MESS/0215_EXTRAs/artwork
ctrlrpath                 ctrlr
inipath                   /Applications/Emulatori/SDL_MESS/
fontpath                  .
cheatpath                 cheat
crosshairpath             crosshair
pluginspath               /Applications/Emulatori/SDL_MESS/plugins
languagepath              language
swpath                    software

#
# CORE OUTPUT DIRECTORY OPTIONS
#
cfg_directory             /Applications/Emulatori/SDL_MESS/cfg
nvram_directory           /Applications/Emulatori/SDL_MESS/nvram
input_directory           inp
state_directory           sta
snapshot_directory        /Volumes/Archivio_HD/Archivio_ROMs/MAME_MESS/0215_EXTRAs
diff_directory            /Applications/Emulatori/SDL_MESS/diff
comment_directory         comments

#
# CORE STATE/PLAYBACK OPTIONS
#
state                     
autosave                  0
rewind                    0
rewind_capacity           100
playback                  
record                    
record_timecode           0
exit_after_playback       0
mngwrite                  
aviwrite                  
wavwrite                  
snapname                  %g/%i
snapsize                  auto
snapview                  internal
snapbilinear              1
statename                 %g
burnin                    0

#
# CORE PERFORMANCE OPTIONS
#
autoframeskip             0
frameskip                 0
seconds_to_run            0
throttle                  1
sleep                     1
speed                     1.0
refreshspeed              0

#
# CORE RENDER OPTIONS
#
keepaspect                1
unevenstretch             1
unevenstretchx            0
unevenstretchy            0
autostretchxy             0
intoverscan               0
intscalex                 0
intscaley                 0

#
# CORE ROTATION OPTIONS
#
rotate                    1
ror                       0
rol                       0
autoror                   0
autorol                   0
flipx                     0
flipy                     0

#
# CORE ARTWORK OPTIONS
#
artwork_crop              0
fallback_artwork          
override_artwork          

#
# CORE SCREEN OPTIONS
#
brightness                1.0
contrast                  1.0
gamma                     1.0
pause_brightness          0.65
effect                    none

#
# CORE VECTOR OPTIONS
#
beam_width_min            1.0
beam_width_max            1.0
beam_intensity_weight     0
flicker                   0

#
# CORE SOUND OPTIONS
#
samplerate                48000
samples                   1
volume                    0

#
# CORE INPUT OPTIONS
#
coin_lockout              1
ctrlr                     
mouse                     0
joystick                  1
lightgun                  0
multikeyboard             0
multimouse                0
steadykey                 0
ui_active                 0
offscreen_reload          0
joystick_map              auto
joystick_deadzone         0.3
joystick_saturation       0.85
natural                   0
joystick_contradictory    0
coin_impulse              0

#
# CORE INPUT AUTOMATIC ENABLE OPTIONS
#
paddle_device             keyboard
adstick_device            keyboard
pedal_device              keyboard
dial_device               keyboard
trackball_device          keyboard
lightgun_device           keyboard
positional_device         keyboard
mouse_device              mouse

#
# CORE DEBUGGING OPTIONS
#
verbose                   0
log                       0
oslog                     0
debug                     0
update_in_pause           0
debugscript               

#
# CORE COMM OPTIONS
#
comm_localhost            0.0.0.0
comm_localport            15112
comm_remotehost           127.0.0.1
comm_remoteport           15112
comm_framesync            0

#
# CORE MISC OPTIONS
#
drc                       1
drc_use_c                 0
drc_log_uml               0
drc_log_native            0
bios                      0
cheat                     0
skip_gameinfo             1
uifont                    default
ui                        cabinet
ramsize                   
confirm_quit              0
ui_mouse                  1
language                  English
nvram_save                1

#
# SCRIPTING OPTIONS
#
autoboot_command          
autoboot_delay            0
autoboot_script           
console                   0
plugins                   1
plugin                    
noplugin                  

#
# HTTP SERVER OPTIONS
#
http                      0
http_port                 8080
http_root                 web

#
# OSD KEYBOARD MAPPING OPTIONS
#
uimodekey                 DEL

#
# OSD FONT OPTIONS
#
uifontprovider            auto

#
# OSD OUTPUT OPTIONS
#
output                    auto

#
# OSD INPUT OPTIONS
#
keyboardprovider          auto
mouseprovider             auto
lightgunprovider          auto
joystickprovider          auto

#
# OSD DEBUGGING OPTIONS
#
debugger                  auto
debugger_port             23946
debugger_font             auto
debugger_font_size        0
watchdog                  0

#
# OSD PERFORMANCE OPTIONS
#
numprocessors             auto
bench                     0

#
# OSD VIDEO OPTIONS
#
video                     auto
numscreens                1
window                    0
maximize                  1
waitvsync                 1
syncrefresh               0
monitorprovider           auto

#
# OSD PER-WINDOW VIDEO OPTIONS
#
screen                    auto
aspect                    auto
resolution                auto
view                      auto
screen0                   auto
aspect0                   auto
resolution0               auto
view0                     auto
screen1                   auto
aspect1                   auto
resolution1               auto
view1                     auto
screen2                   auto
aspect2                   auto
resolution2               auto
view2                     auto
screen3                   auto
aspect3                   auto
resolution3               auto
view3                     auto

#
# OSD FULL SCREEN OPTIONS
#
switchres                 0

#
# OSD ACCELERATED VIDEO OPTIONS
#
filter                    0
prescale                  1

#
# OpenGL-SPECIFIC OPTIONS
#
gl_forcepow2texture       0
gl_notexturerect          0
gl_vbo                    1
gl_pbo                    1
gl_glsl                   0
gl_glsl_filter            1
glsl_shader_mame0         none
glsl_shader_mame1         none
glsl_shader_mame2         none
glsl_shader_mame3         none
glsl_shader_mame4         none
glsl_shader_mame5         none
glsl_shader_mame6         none
glsl_shader_mame7         none
glsl_shader_mame8         none
glsl_shader_mame9         none
glsl_shader_screen0       none
glsl_shader_screen1       none
glsl_shader_screen2       none
glsl_shader_screen3       none
glsl_shader_screen4       none
glsl_shader_screen5       none
glsl_shader_screen6       none
glsl_shader_screen7       none
glsl_shader_screen8       none
glsl_shader_screen9       none

#
# OSD SOUND OPTIONS
#
sound                     auto
audio_latency             2

#
# PORTAUDIO OPTIONS
#
pa_api                    none
pa_device                 none
pa_latency                0

#
# CoreAudio-SPECIFIC OPTIONS
#
audio_output              auto
audio_effect0             none
audio_effect1             none
audio_effect2             none
audio_effect3             none
audio_effect4             none
audio_effect5             none
audio_effect6             none
audio_effect7             none
audio_effect8             none
audio_effect9             none

#
# BGFX POST-PROCESSING OPTIONS
#
bgfx_path                 bgfx
bgfx_backend              auto
bgfx_debug                0
bgfx_screen_chains        default
bgfx_shadow_mask          slot-mask.png
bgfx_lut                  
bgfx_avi_name             auto


ui.ini

Code
#
# UI SEARCH PATH OPTIONS
#
historypath               history;dats;.
categorypath              folders
cabinets_directory        /Volumes/Archivio_HD/Archivio_ROMs/MAME_MESS/0215_EXTRAs
cpanels_directory         cpanel
pcbs_directory            /Volumes/Archivio_HD/Archivio_ROMs/MAME_MESS/0215_EXTRAs
flyers_directory          flyers
titles_directory          titles
ends_directory            ends
marquees_directory        marquees
artwork_preview_directory "artwork preview;artpreview"
bosses_directory          bosses
logos_directory           logo
scores_directory          scores
versus_directory          versus
gameover_directory        gameover
howto_directory           howto
select_directory          select
icons_directory           icons
covers_directory          /Volumes/Archivio_HD/Archivio_ROMs/MAME_MESS/0215_EXTRAs
ui_path                   /Applications/Emulatori/SDL_MESS/ui

#
# UI MISC OPTIONS
#
remember_last             1
enlarge_snaps             1
forced4x3                 1
use_background            1
skip_biosmenu             1
skip_partsmenu            0
last_used_filter          "Custom Filter"
last_right_panel          0
last_used_machine         apple2e
info_audit_enabled        0
hide_romless              1

#
# UI OPTIONS
#
infos_text_size           0.75
font_rows                 30
hide_main_panel           0
ui_border_color           ffffffff
ui_bg_color               ef101030
ui_clone_color            ff808080
ui_dipsw_color            ffffff00
ui_gfxviewer_color        ef101030
ui_mousedown_bg_color     b0606000
ui_mousedown_color        ffffff80
ui_mouseover_bg_color     70404000
ui_mouseover_color        ffffff80
ui_selected_bg_color      ef808000
ui_selected_color         ffffff00
ui_slider_color           ffffffff
ui_subitem_color          ffffffff
ui_text_bg_color          ef000000
ui_text_color             ffffffff
ui_unavail_color          ff404040