Well if it's not in the SNDH archive it hasn't been ripped and converted yet. Converting older musics is always a custom job as they are probably not in a standard format that SNDH-Converter recognises.
You need to rip the music aswell as the replay-routine. SNHD-format always combines both. Here's a documentation about the format:http://sndh.atari.org/fileformat.php
If you don't know how to code assembler I doubt that this will be easy... I suggest to contact Grazey directly: grazey(at)atari.org.