[Forums] background-image & mails

I want to make a nice mail with a heading with a background.

This is not working very smoothly...  :-(

During design it was not possible to get that image as a background (it was as if the image was not found : background coloring was working without problems and the link to the image was correct (it was dragged) ).

When I made a webscreen with a div that uses the same background (to check if this maybe only works in webscreens) the background was there without any problem.  And...  suddenly the background in the mail became visible.  (?)

So the design of the mail was ready (with a little hack because when I remove the webscreen the background in the mail is gone).  

The result in the mailbox however...  is still without background image.

Anyone with an idea how to get background images in mail div's ?