[Haskell] Literate Haskell editing with Emacs and MMM: the $ operator

I've been editing literate (LaTeX-based) Haskell code using Emacs and MMM-mode, using the instructions posted in http://www.haskell.org/pipermail/haskell/2006-April/017855.html There's one annoyance, however: the $ operator in Haskell code ends up being interpreted as the beginning of math mode, completely messing up any font-lock colo(u)ring. Has anyone else found this, and has anyone come up with a good solution? Thanks, Julian