Post any defects you find in the released or beta versions of the ImageMagick software here. Include the ImageMagick version, OS, and any command-line required to reproduce the problem. Got a patch for a bug? Post it here.
At least in my $PREFIX/etc/ImageMagick-6/delegates.xml the comment names it bimodal, not bimodel -- and the commands I tested with -verbose indicate that only bimodal does work as advertised...