Looking at the BB MIDI manual, I did not see anything related to Program Change (PC) MIDI data being sent by BB from a song/midi file so it might not be possible. You could try adding PC data to a song and see if BB plays it back and send it out on MIDI out. I’ll be curious to know too!
Thanks! The Infinity looper uses CC switches to increment and decrement the program number. But, it doesn’t look like it accepts a direct program change.