Yamaha DTXpress/DTXplorer/DTXtreme

I'm trying to setup a sequencer on my laptop so I can play along with 
my DTXpress, but I'm having problems getting setup properly.

I've had my DTXpress for about 9 months now, but I'm just starting to 
get into the MIDI side of it. I'm a complete MIDI novice. I read some 
of the previous posts here and went out and bought a MOTU USB MIDI 
Interface for my Dell laptop computer running Win98. I had no problem 
setting it up and before long I was able to use DTXchange to upload 
some user kits to my DTXpress.

Now I'd like to try to play along with some MIDI files. I've got a 
demo version Cubase VST and a registered version of n-Track Studio 
v2.2, but I'm having problems getting them to work properly with the 
DTXpress. I've gotten both sequencers to play the MIDI file through 
the DTXpress but I usually end up hanging/crashing my computer when I 
try to adjust settings.

On Cubase, I can mute the drum track but that causes problems with 
sounds I get from the drum pads. For example I'll hit the kick and 
hear a kick + bell, or I'll hit a tom and hear the tom + a sax.

On n-Track studio, I can only mute the drums on a few MIDI songs and 
when I do it also mutes the DTXpress pads so I can't play along.

If any of you use either of these programs, how do you have it setup? 
What options do I need to set in the program and in DTXpress?  Keep 
in mind that I'm not really familiar with either of these programs. I 
looked through the archives here and didn't really see anyone 
describing exactly how they set Cubase up.

Thanks,
Chris