I was ok with your question until the last sentence. I recall there being some way to set up velocity zones in a drum rack, but I’d have to do more research than I have time for at present. Essentially, you need to do a couple steps. 1] Look at your kit in the BB Manager drum kit editor screen, and make a list of drum tones, midi note locations, and velocity levels. Essentially, make a written map of your kit. 2] Consult the Ableton manual for assistance with the Drum Rack instrument. I believe there may be a 16 tone limit for each rack, but I do believe you can map the notes to midi locations as you see fit. If your kit has more than 16 tones, you may need multiple Ableton drum racks. 3] Find the location of the wav files used in the BB drum kit on your HD. Copy it to a new work folder on your HD that you will use to build the drum rack(s) in Ableton. 4] Build your racks, program you tracks. When done, if you have more than one track, merge the multiple tracks into one. This file can then be exported as a midi file and brought into BB manager as part of a BB song.
Note - I would never do it this way. It’s a backward approach. Rather, I would program a track in Ableton using a drum rack up to 16 pieces, then build a BB drum kit with those 16 pieces in the locations I mapped in Ableton.