This is awesome. Both that it now does it, and John's technique too.
I have a zillion midi files from all kinds of music - well over 1000 files, and I want to build up a bunch of them to go do cheesy solo piano gigs for brunches and wedding receptions and such, so this will save me countless hours. At $150/hour for the wedding receptions, it is well worth doing for me, as a means to buy new gear.
(I will leave the keyboard tracks for the songs for me to play, but will have all of the backing tracks to get a fuller sound).
Thanks, John, and thanks, Sonar.
Bob Bone