Like it says on the tin.
This time I actually wrote a program to convert from Impulse Tracker .IT format to DefleMask .dmf format. So I took the MIDI into FL Studio, cleaned it up and prepared it for the Genesis, exported the MIDI, imported that into OpenMPT, exported an IT file, ran that through my converter, loaded THAT up in DefleMask, assigned all of the instruments, and rendered out a WAV file.
As a side bonus I also exported an actual Sega Genesis ROM file containing the song in VGM format. It sounds pretty much identical.