WOOHOO! SUCCESS! I found the prob - the XV MIDI THRU was set to OFF (system parameter), so the EWI wasn't getting back into the PC. A cool drawing on page 95 of the manual shows the setup.

OK, I'm recording into BIAB now. However, when I playback what I've recorded with the BIAB song the track seems to be a fraction of a beat AHEAD of the BIAB song. I guess it's a latency setting somewhere, but please advise. I thought that what I played in time with BIAB playback would be recorded in time with it, not slightly ahead. Where do I make this adjustment, and how? I mean, I guess I want to ADD latency to the part I'm playing?