After trying to get the imagewriter to fire the pins in a "simple" way which didn't work properly, why not try to hook up a 74123 according to the schematic.
It wouldn't fire at all until I got the right values for the R and C which didn't appear on the sams schematic correctly, but were specified on the apple schematic as .022uF, 18K ohms, and 1000PF, 10K ohms:
TTL74123(config, m_pulse1, 10000, 1000e-12); // second stage (hooked up to 1 section of 74123)
m_pulse1->set_clear_pin_value(1); // not clear
TTL74123(config, m_pulse2, 18000, .022E-6); // first stage (hooked up to 2 section of 74123)
Now 2gs beagle write will print on Standard/Best: