I havent really tried it because Im running mine thru cubase but in the "reference guide" on page 183 it says the n264/364 reads midi files so just slap one on a disk, cram it in the kboard, then go to disk mode, and go to "5A Load SMF Directory Ok?".
*To do that just press the button with "Cursor Perf Edit/RPPR" above it until it comes up on the screen*
then select the file load it etc..
*To do that just screw around with it until it works, I dont know the exact sequence*
and make sure you select the seq when you want to play the file. You may have to change some of the instruments in the channels if it sounds like shit.
Hope to have helped