We recently bought a PR-804, and even though it is one of the best sounding Digitals out there, the manual is pretty useless. We are currently trying to take an SMF file that was recorded on a Roland Digital and change the instruments to the NX sounds on the PR804 and save the changes. We can change the instruments, and play the song with the changes, but once you stop the play, it reverts back to the original SMF sounds. Any suggestions?