must have different midi notes from yours, i.e. when you play on a pad a
midi note is sent through the canal 10 to your pc, and this note trigs
another voice from your sound card, but for example if your snare pad sends
a E1, the sound card will play the voice which is set with the E1(which is
not necessairy a voice of snare). Therefore you must change the midi notes
sent by your kit(it will note change the voice played by the DTXpress
brain). It is in "voice" just after the decay. I think that you can find
easily the midi notes used in the cubase drum kits.
Be carefull: there is another problem which can arrive. In the midi setup be
carefull that the midi thru option is off because when it is on the midi
signal received by the card is sent through the midi output and if the
output is linked to the midi input of your dtxpress brain it can cause loops
of triggering.
For the canal, the drum canal is usually the 10. (But you can change in your
kit the canal through which the midi notes will be sent to your sound card.)
The midi system is very simple, you must understand that only midi notes are
sent, and through 16 canals(or more)(usually a canal=a instrument). The midi
note only trigs a voice in the bank of your sound card.
good luck