Our project (and probably future project) makes use of PNG transparency, and in order to support it in IE6 we're using a .htc (HTML Component) script using the IE proprietary CSS 'behavior' setting.
However, htc files are not allowed to be uploaded - is it possible to change this setting?
You can find more about the script and how it works here: http://www.twinhelix.com/css/iepngfix/ and here: http://bjorkoy.com/past/2007/4/8/the_easiest_way_to_png/.