[plt-scheme] debugging DrScheme languages

I'm trying to implement a unit-based DrScheme language and DrScheme 
isn't picking it up. I've used the honu collection as my guiding 
example, and I've got the tool.ss and info.ss modules set up similarly. 
I've got my collect's directory corretclt setup in the PLTCOLLECTS path 
(and I verified that (require (lib "foo.ss" "foo")) works).

Yet when I restart DrScheme, the icon I've given the collection doesn't 
show up, and the language doesn't appear in the languages dialog. I 
tried PLTDRDEBUG to see if that would give me any clues, but I got nothing.

Any suggestions on a) what I could be missing, and more generally b) how 
to debug problems implementing DrScheme languages? E.g., other special 
flags like PLTDRDEBUG..

Thanks,
Dave