Hi,
forgot to mention midifiles seem to work via "Sound Play" in the SD menu.

It's 7 in the morning here, so maybe I'm still dreaming (heehee)

Ammendment
I think I may have found a way to load midi's to your SD Card
Try the following Press
SD Load Button next
SD Tools Button ( top left)next
SD SOUND Tools Button (bottom right) next
Copy from disk.

Don't know how flexible this system is , please let me know if it works.

best wishes
Rikki