Can't make transparency work with white

You've probably seen many cool uses of your Latex engine, and this has probably been done before, but I was able to add a [latex] code to my discussion board. Members can now include complex equations in their messages. Here's a link to my announcement of the feature:

http://www.evcforum.net/cgi-bin/dm.cgi?action=msg&t=13879

--Percy