Hi
On the FP-4 I can record up to 3 tracks of MIDI to internal memory and play them back simultaneously with live playing. It is also not difficult to transfer the contents to a MIDI sequencer / DAW through a MIDI cable or USB.
What I would like to do is to edit the recorded tracks on the computer (fixing some mistakes, fiddling with the drums track, etc) and then put the result back in the FP-4 memory so I can play it.
When you transfer the songs to the sequencer, are you using MIDI clock from the FP-4 locking it to the sequencer?
I've looked at the MIDI implementation chart, the FP-4 sends clock, but doesn't receive it.
So I think the only way to reload the song back into the FP-4, once it has been tweaked would be to have a clear song in the FP-4.
Have the FP-4 as the clock source, but set to record, so when you hit play the sequencer plays, but the FP-4 records what is played into it.. You might even need to do this a track at a time, or it might record all the parts played into it all on to 1 track.
I'm not even sure this will work, but you could try..