Warum so? Ein einzelnes Div sollte doch auch reichen.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<style type="text/css">
<!--
body
{
margin:0;
padding:0;
}
#header
{
margin:20px 0 0 0;
padding:0;
height:100px;
width:100%;
background: url(logo_hg.png);
background-repeat: repeat-x;
text-align: center;
}
-->
</style>
</head>
<body>
<div id="header">
<img src="logo.png" alt="Mein Logo" />
</div>
</body>
</html>