Just a shot in the dark, but perhaps you can narrow it down by recording some program changes from your outboard? It might just be a convention problem, as bank and program changes can work differently on different devices. Some devices need a bank select message if i remember correct. Not too much hoping, though. But a chance.
Frank
EDIT: Not sure, but I thought maybe this can help?
http://forum.cockos.com/showthread.php?t=23734