Try this:
Code:
{* $Id: head.tpl,v 1.58 2006/03/17 08:50:44 svowl Exp $ *}
<table class="Header" width="920" border="0" cellspacing="0" cellpadding="0">
<tr>
<td><table cellpadding="0" cellspacing="0" align="center" width="920">
<tr>
<td width="550"><a href="{$http_location}/"><img src="{$ImagesDir}/minilogo.gif" width="380" height="120" alt="" /></a></td>
<td width="370" align="right"><br />
{if $usertype eq "C"} {*include file="customer/top_menu.tpl"*} {/if} </td>
</tr>
</table></td>
</tr>
</table>
<table cellpadding="0" cellspacing="0" align="center" width="100%">
{if $main ne "fast_lane_checkout"}
<tr>
<td class="HeadLine" height="45">
{if $usertype eq "C"}
{/if}
<div align="center">
{literal}
<script src="skin1/images/xaramenu.js"></script><script language="" src="skin1/images/trolley.js" Webstyle4>
</script>
{/literal}
</div></td>
</tr>
{else}
{/if}
</table>
This puts the 1row/2 column table inside a 1 row/1 column table that has the Header class applied. Kind of clunky, but it might work, after a bit of tweaking.