In the original kit labeled "Two Basses" that you mentioned, there really are only two notes (if I recall, as I don't have access to the DM Pro at the moment). Usually one of the notes is some "C" note somewhere, then every note after is tuned up to mimic an increase in pitch. Go to the Two Basses kit, dial up note 60, then hit the Tune button. Then hit Drum, move to note 61, and hit tune again. It should show an increase in tuning.
If you go to the Bonham kit again (one of my favorites =) ) and load up the Slap Bass sound as you did for notes 48, 49, etc. Then go to note 49 and tune it up a step, note 50 2 steps etc. Just do a couple and see if it works.
I use a TrapKat as well as the Zen, and on the DM Pro I did just as you are trying to do - make a drum kit with one part of the setup, and a chromatic part also. On the TrapKat it's kinda neat because you can set up to 4 notes on a pad, so you can play chrods as well as notes.