3 part Background?

[ComoEstaEso-com]

Hello everyone,

I am trying to add a background image to our forums.
I was able to add it just fine with the doc_background Style Variable.

Awesome!
Thing is, it is repeating vertically.

The background image I want to use, I can slice into 3 parts: top, middle, bottom.
Idea being that the "middle" part repeats depending on the length of the page, until it gets to the bottom's upper part.

How can I achieve this?

When I used the doc_background, yes the image loaded... yet obviously, repeating.

If you visit my forum on my user name, you will see the image.

Thank you!