EXS 24 Logic Sampler Users Group

I've downloaded from the files area and have used the defs for 
the LM4 kits and they work great.  I have the LM4MkII with 
additional kits. I was using Cubase at one time. I went to Logic 
on OS9 and now moved to OSX. (Although my Pro upgrade 
hasn't arrived yet)
I'd like to know how difficult it is to write additional defs for the 
other kits. Is it possible to alter the existing defs for the other
LM4 kits I have?
Any info would be appreciated.

Thanks,
Fred