Embedding a flash header banner into a CSS sheet.

Hello,

I recently created a site for a client and he has requested that I add a flash banner to replace the existing header jpg image. The dimensions of this object are width 926 x height 226. I have been able to embed .swf into php before but am struggling with this in CSS. Can someone assist me with the code. Below is a snippet of my CSS coding that shows the original image "header_bg.jpg" that needs to be replaced. The flash file is located /images/ocrintro.swf. Thanks in advance!

/*------HEADER------*/
.top-menu{height:41px; padding:29px 0 0 20px; background:url(images/top_menu_divider.gif) 25px 34px no-repeat;}
.header{width:955px; height:226px; float:left; background:url(images/header_bg.jpg) 30px top no-repeat;}
//.header-right-block{width:200px; height:226px; float:right; padding-right:21px; background:url(images/login_form_bg.jpg) left top no-repeat;}
.logo{margin:62px 0 53px 389px; width:257px; height:84px;}
//.header-search-form{padding:3px 0 0 29px; height:18px; background:url(images/search_form_bg.gif) left top no-repeat; margin:0 0 0 530px;}
//.header-breadcrumb-row{height:23px; background:url(images/breadcrumb_bg.jpg) left top no-repeat;}

h1.site-name { font-size:17px; display:block; padding-top:15px;}
h1.site-name a { color:#0d0d0d; text-decoration:none; text-transform:none; font-weight:bold; font-family:Arial;}
.slogan { padding:7px 0px 0px 414px; color:#44523a; font-size:18px; text-transform:uppercase;}

.pr-menu {padding:15px 0 0 0;}
ul.primary-links {margin:0px; padding:0; list-style:none; text-align:center; }
ul.primary-links li {float:left; text-transform:capitalize; padding:2px 40px 5px 36px; background:url(images/top_menu_divider.gif) right center no-repeat;}
/*ul.primary-links li:hover { background:url(images/bg-li.gif) top left no-repeat;}*/
/*ul.primary-links li a.active {color:#48A3DB;}*/
ul.primary-links li a {color:#FFFFFF; text-decoration:none; font-size:14px; font-weight:normal;}
ul.primary-links li a:hover { text-decoration:none;}
/*ul.primary-links li.last { padding-right:0;}*/