OK, I may have a fix for you.
Here is my MIDI/AUDIO Setup. With this setup (and only this setup!)
1) I can use Shift-Return to play the Chord from the Chord Sheet to Use VSTi/DXi soft synth [which by the way, is the box everyone should have checked]. But you need to setup the VSTi/Dx Synth properly. I use SynthFont: VSTSynthFont64 as you see in the picture. Best sounds and features no matter what anyone else tells you.
2) This setup will play the RT Pad from the "_Turnawy.sty Turn Away alternate 8ths build" on the Utility track with no additional sounds. <-- Your .SGU
3) This setup allows me to route my midicontroller keyboard to playalong with BIAB.
Its all in the picture. By the way, when you make any changes to these setting, close BIAB and reopen it for them to take effect.
I would be glad to provide a video if needed. But my narrations will be in english.
Dan