Hi bharris
You will have to go into JABB to find and alter it's melody channel (whatever it is) so that it allows it to play from BIAB channel 4 - once you have had success then save the set up (as say BIAB1) so that each time you open JABB you can load that saved set up
You could alter BIAB Melody channel from 4 until you find the channel that plays in JABB but this then disrupts your default workings in BIAB
jazzman