are we talking about emulation? - should work with real hardware too,
but emulation is easier.
try those prepared
hdf files, mount one together with your cdrom and copy everything from cd to the hdf.
in the emulator you have to tick bootable for the hdf.
maybe you have to edit the startup-sequence, look for cd32 specific commands,
disable them --> ; infront of the command.
furthermore, if you have some references to cd0: you may add:
to the startup-sequence on your hdf.