I use a Tyros keyboard with my PG software. If you are wanting to use, say a Yamaha style as your background music, you would want save it as a midi file first (from your keyboard) and use RB to open it and add or generate any "extra" parts.

If you are wanting to record a simple melody or instrument part, Biab will work for that. But, if you are wanting to add more then two parts or tracks, RB is what you will want to use for that. It has numerous midi channels/tracks where Biab only allows you to record to either the melodist or soloist channels.

RB is suited for multitracking much better then Biab is. You can use the sequencer in Biab for adding parts, but it is more tedious work to do so. It can be done tho.

A little more info would help us point you to the proper PG software to use.

Trax