Unlike the Windows version, BIAB Mac does not allow you to assign virtual instruments like JABB to tracks internally.. You will have to use Core Midi to access those sounds externally. Here is the help page. Look at the Core Midi section:
http://www.pgmusic.com/tutorial_bbm_nosound.htm

You will need Midipipe too:

http://www.macupdate.com/app/mac/10541/midipipe


Fred Grittner
2020 iMac, Sequoia 15.5, Logic Pro
https://fredgrittner.bandcamp.com