find() in IE

find() in IE

<html>
    <head>
        <script language="javascript" type="text/javascript" src="jquery-1.4.4.min.js"></script>
       
        <script language="javascript" type="text/javascript">
            var xml = '<?xml version="1.0"?><root><t1>c1</t1><t2>c2</t2></root>';
            alert($(xml).find('t1').text());
        </script>
    </head>
    <body></body>
</html>

in FF this script returns 'c1' and $(xml).find('t1').length == 1
in IE - empty string in alert and $(xml).find('t1').length == 0
How to modify this script to work in IE?