Repeating background but with rounded corners at the top

[cawd]

I've seen this done several ways, but I'm looking for a simple solution. The main content area is white, with rounded corners at the top and a shadow around the top and both sides.(See image below) I've saved out the image in 2 pieces, one contains the top 72px or so with the rounded corners. The other is a slim piece, the same width as the top piece, including the shadow. I've created a div and gave it an id="contentcontainer", where all of the content for the pages will rest. Inside of this div is where I need these images to show up. The top image with the rounded corners needs to always be at the top and then the slim piece needs to repeat the length of the content as well as being fluid to accommodate differing amounts of content from page to page. Make sense? Any simple solutions out there? THANKS!