well... no thats not true...
(i'm back and now i have an answer)
here try this, which works perfectly for me in both ie and mozilla:
PHP Code:
<html>
<head>
<style type="text/css">
html, body { background-color: red; height: 100%; margin: 0; padding: 0;
color: white; text-align: center; }
div#centered { border: 0; background-color: white; height: 50%; width: 50%;
position: absolute; left: 25%; top: 25%; color: black; }
</style>
</head>
<body>
<div id="centered">
vertically centered div
</div>
</body>
</html>