Originally Posted by robcfg
The CAS file for Dragon/CoCo is just a bit dump, nothing else.

Are you sure? This page would seem to indicate that it can be just a bit dump, but it certainly seems to be capable of a bit more than that, which I suspect is part of the issue at hand: http://archive.worldofdragon.org/index.php?title=Tape%5CDisk_Preservation#CAS_File_Format