Yamaha DTXpress/DTXplorer/DTXtreme

Apparently there is an age-old state of confusion that exists with 
DTXpress systems and the relationship between drum kit definitions, 
voices, and self-recorded (pad) songs, and I've fallen victim to it.

I've read postings here and elsewhere suggesting changing songs' 
MIDI channel to 6 and PCNo to the kit no (or not), and have only had 
success actually using MIDI channel 10 in retaining voice mappings.

Here's the aim: To record any number of songs, with voices from any 
number of kits whose definitions may or may not be retained in the 
system after recording, and initiate playing of those songs from any 
pad in any kit so that the original voices of the song are still 
heard.

Is this possible?

I've figured out how to record a song, map it to a specific kit, and 
assign a pad in (that) kit to play the specific song.

What I can't do yet:

- record a song and have it play back in the original voices where 
the kit definition (or original voices) no longer exists

- start multiple songs, originally recorded with different kit 
definitions from a single kit's pads that have nothing to do with 
the recorded songs.

Should I be looking at a better understanding of internal MIDI 
channels and pad songs (ref. man. 2-7, pg 20-21)?  It appears that 
the kit definition needs to be retained for the song to sound 
correctly.

The reference manual suggests up to 3 pad songs can be defined in a 
kit, being transmitted on different MIDI channels.  Does that mean 
that those pad songs have to have been recorded with the existing 
voices of the corresponding kit used to initiate playing through a 
pad?

Hey, thanks for any inspired responses. This thing can do more than 
I've figured out, but it would be nice to have a clear picture what 
a realistic expectation would be.

Galen