Needing CSS help

For the new developer site, we got a nice proposal for a box from our artist Nuno. It looks like the following:

The header was simple, but I have no idea how to create a prototype for the box. Unfortunaly, I am not an expert with CSS, but I don’t think tables are the way to go here. I’ve put together a package with the cut down PNGs for the borders and the edges and a test HTML file from the approach I have so far. If you know a solution, please leave a comment. The new developer page will thank you 🙂

Update: I got a lot of replies via PM, since the comments seem to be broken atm. I will look into both the submissions and the commenting problem. Thanks to all of you!