Dear Arkady,
Thanks for the great tool!Just a small suspected typo report: it appears that in the cmcbx.htf the Unicode fo the glyph \x19 should be U+2116 (Numero sign), not U+2216 (Set minus). I am attaching the output of pdftex testfont for your convenience.
Thank you for the report and your kind words. You are right, there was a typo. I've fixed that in the TeX4ht sources.
Best regards, Michal
