I recommend Natsukiso's MML maker [1RW33KNE]. The Japanese text is almost ignorable.
After you finish composing, go to MENU and select "EXPORT MML", save it, then type these in your program and enjoy!
VAR STRMML$=LOAD("TXT:YOURFILENAME",FALSE)
BGMPLAY STRMML$
Replace YOURFILENAME with the actual file name you saved, of course.
i would offer to help but i dont have the game also i would help do character designs but you already have somebody to help with that. WHHHHHY!!!!!!!!!!