Yamaha DTXpress/DTXplorer/DTXtreme

Help!!!!!!!!!!!
I recently bought a DTXpress kit and I am quite pleased.  I'm a long time 
acoustic player and this is my first e-kit.  So far I have only one question.
The problem is that, when I go to record track two, I can't seem to isolate
track one from the whole process of playback.  Moreover, I can't figure out
how to tell the DTXpress NOT to change the kit sound for the first track
(sorry if this isn't making much sense).  Example:  I want to lay down a 
jazz drum kit part and then come back later and put some percussion over
the top (for sake of discussion let's say I choose the Latin Perc. kit for the second track).  Now, when I go to lay down the percussion on track two, the 
DTX wants to play the first track as a Latin Perc. kit as well instead of 
remaining a Jazz drum kit.  From what I can tell, it does this because I chose Latin Perc. for the second track and it thinks I want both tracks as that? Help!  I'm confusing myself!
How do I record the second track as percussion while still hearing the 
first track as the jazz kit?
--Aaron
P.S.  I've found that the sound quality of the DTXpress in general is greatly
enhanced with a pair of really good quality speakers.  Mine just happen
to be 2 Yamaha 15's.  Hmmmmm......???????