I am too new to these forums, so I am unable to post URL Links.  But, you can easily locate instrument definition files for the Casio XW-P1 and Casio XW-G1 by doing a search for casio xw instrument definition file in your favorite search engine.  I have tried it in Google, and the first two search results right now are links to the .INS file that Mike Martin from Casio America, Inc. created for the Casio XW-P1 and the .INS file I created for the Casio XW-G1 (Based on Mike Martin's XW-P1 .INS file).
 
These babies make things a whole lot easier inside of Cakewalk Pro Audio and the Sonar X series.  I just wish there was an easier way to share them with people.  If you know someone with a Casio XW synth who can benefit from these files, please spread the word. 
 
I uploaded them to Cakewalk, so maybe they will include them in a future .ZIP of the user-created .INS files.
 
 
-Sheldon Sims-

I modified Mike Martin's Casio XW-P1 V 0.5 Instrument Definition File to include bank 100 (User PCM Melody) and bank 125 (User Drums).
 
Now we can access 100 more user tones (piano, strings/brass, guitar/bass, synth and various) and 10 user drum kits.
 
I posted the modified file on the Casio Music Forums and the Casio XW-G1 and XW-P1 Synthesizer Group on Facebook.