Ray,
The SD2 has two midi connectors on the back. The MIDI In and the MIDI Thru. The MIDI In takes the information from whatever source, your keyboard, or BIAB, and runs the information to the sounds, the MIDI thru sends the data coming in out to another synth.

Yes, you *can* use the SD2 with both BIAB and a Master Keyboard at the same time.

Using a MIDI interface, your choice of which, run the MIDI OUT to the MIDI In of the SD2.
Run the MIDI OUT of the Keyboard to the MIDI IN of the interface.

Inside BIAB, open your MIDI Device Drivers under the Options tab, and select the MIDI interface as your MIDI In device, and then the MIDI Interface as the output device (so, if you're using an Audigy 2, you would use the MIDI interface on that, and select the Audigy MIDI In and Out as your interface). Then, go to Preferences, MIDI Options, and select MIDI Thru and turn it On. This will take the incoming data from the keyboard, and re-route it back to the SD2. You *should* be able to select the instrument patch you want to hear when you select the Thru instrument and whatever sound you want to hear from the drop down menu, or the Higher Banks dialog box, if you use the SD2 .pat file.

Gary

I'm blessed watching God do what He does best. I've had a few rough years, and I'm still not back to where I want to be, but I'm on the way and things are looking far better now than what they were!