The issue with the VB commenting is related to the underlying prettify script being used (http://code.google.com/p/google-code-prettify/).  Not quite sure if google has it on the prettify bug list but there are a few workarounds to the vb commenting issue posted here: http://meta.stackoverflow.com/questions/6812/vb-net-vbscript-syntax-highlighting-does-not-properly-support-comments