Yamaha DTXpress/DTXplorer/DTXtreme

I'm sure this question has been answered before in this group, but I 
didn't see it in the archives.  I use cakewalk in my home studio, and 
I would like to be able to select from my user kits on the dtxpress 
via cakewalk.  I have read some things about using a program change 
sysex command, but I'm not clear on how to accomplish it. I do know 
that when I specify a specific "patch" (0-127) in cakewalk, it 
changes the drumkit on the dtxpress, but unpredictably.  Since the 
dtxpress only has 80 kits total, how can this be controlled through a 
software sequencer?

Thanks in advance for your help.

Mike Burke