Bluezplayer, if you have buttons on your keyboard that can be programmed to send user defined midi messages, then those buttons could be used for triggering variations. The pad buttons on my keyboard work only in arranger mode, they don't send midi messages in midi mode. But if pad buttons did send midi messages then you could e.g. program pad1 to send a D0 note, pad 2 to send a D#0 etc. Then in OMB assign the variation triggers to these notes and you would be able to trigger variations with the pad buttons.

It's not clear to me what you mean with the "assignable knobs" on your keyboard. Are these buttons that can send user defined midi messages? Can they send note-on messages as well or just Control Change messages? It wouldn't be that difficult to let OMB recognise certain Control Change messages as variation triggers.

JM