Emu XL-7 & MP-7 User's Group

Hey,
Are the ROM cards from the xx-7 line interchangeable with their sound 
modules? For instance, could I purchase a Mo'Phatt sound module from 
eBay, and install the Protean Drums ROM into it? I'd much rather 
rather have the MP-7 with the Protean Drums ROM installed in it, but 
it might be a cheaper alternative for me to go the module route. 
Thanks to anyone who's able to help!
Fab