[plt-scheme] Emacs modes and s-expression comments

I use emacs and "quack" mode for editing Scheme source.  It's nice
overall, but "#;" comments confuse it - it considers them line
comments, and they ruin parenthesis-matching for entire files.  Does
anyone know of a good fix, workaround, a version of quack that
understands these, or a better emacs mode I should be using for
Scheme?  Thanks.

--
Carl Eastlund
"Cynical, but technically correct."