I have the SC-155 (same thing in a different case w/sliders).
I don't know about editing. Perhaps that MIDI editing software on that YoungMonkey site (do a google search for YoungMonkey and Amiga).
The SC-55 is not really editable. It's not a synth, but rather a "tone module". I mean, you can sort of tweak some of the parameters (like chorus, reverb, ADSR, etc.) but it doesn't remember these when you shut it off.
Bars & Pipes has a tool just for controlling patch changes in the SC-55. I love it for that.
The Patchmeister might have a librarian for the SC-55....but on the other hand I'm not sure why it would need it, as it's not really an editable box.