If you mean the gradient background when you say 'vignette', then I suppose the easy quick fix (but not the kosher fix) would be to put the body css style in to the head of your documents, and see if IE can wiggle its way out of that one.
<style type="text/css">
<!--
body {
background-image: url(images/bg.jpg);
background-repeat: repeat-x;
}
-->
</style>