Ok, I’ve been digging now for… about 60 seconds, and I thought you might be
interested in the result:
http://www.4front-tech.com/pguide
follow the link to MIDI programming…
Follow the link to the hacked-up version of the spec (Unless you want to pay
money for the “official” spec 
I’ll keep on digging, but I thought I’d give other diggers a start.–
– Michael Samuel
Don’t trust anything I say, just give it consideration.