I've not played a BassStation 2 (though I once upon a time used the original Bass Station quite a bit), but if the BassStation 2 sends MIDI CCs when you turn the knobs then you can also record the knobs into the MIDI track on the fly. Or record the notes as MIDI first then record the knob turning into the same MIDI track afterwards by overdubbing it.
Which can be much easier than messing around drawing envelopes or controller stuff in Sonar.