Adding swf to css

I have a css based page with an image for a banner.
I have created an swf file to replace the banner that I can't get to show up on the page. This is the css section for the image banner now.

.banner{
background:url(images/bannerbg3_13.gif) repeat-x;
height:130px;
width:100%;
border-bottom:3px solid #1553B9;
}

When I change the url line to match the swf it doesn't show. There is obviously more to it than that.

The line on the html page is
<div class="banner">

Where do I need to make the modifications and what kind?
Thanks in advance
www.virtualwebvideo.com

You can't set a flash file as a background image simply because well...its not an image. You will need to embed it into the document. Check out http://blog.deconcept.com/swfobject/

Thanks for taking a look. Got it handled. Trial and Error.