HI
First make sure you have the keyboard set as a midi input in BiAB midi settings..
On the normal chord sheet screen look at the mixer for the THRU Track just below the Soloist track,
Select your play thru patch Voice from here.
Thru is sent to you midi out device selected in mid setting, if you have routed midi to your VST DXI synth those are the voices you hear.
If you are in record mode the midi data gets sent from here to the Melody or Soloist track
as well and is recorded as note data.
The voice / patch that you hear on play back is the voice selected for the melody or soloist track.
It is up to you to choose the melody or soloist track voice and the THRU track voice to be the same if that’s what you want,
If you do not set a voice for the THRU track it will use the default Piano .
But still what you hear on playback will be what ever voice you have chosen for the Melody or Soloist Track.
You can also work with the soloist track if you select it
Because when you click record a box pops up allowing you the choice of recording to the Melody or Soloist tracks.
for info
THRU = midi ch 5
Melody = midi ch 4
Soloist = midi ch 8
This is why each track can have its own voice /patch
I think that will get you going.
Mike