Hi Eric,
if I understand correctly, are you trying to turn a KN7 song into a midifile so you can edit and enhance it in your computer.
The Kn7 songs can be turned into midifiles including using the nx voices.
If so

Record Song
Press COPY PASTE
Press APC to SMF
Pick the song parts & tracks
Press Convert
Press Disk Save
Save as SMF
I turn
Panel Header on
1 Measure space on
Save as NX

That should hopefully give you a midifile of your song. Save it as a Technic song first as I don't think the above can be undone.

I'm going away for a few days, so if you can't make sense of what I wrote I'm sure Alex or one of the members will be able to help you.
Knowing me, I've probably misunderstood the question ( heehee)

best wishes
Rikki