You can make r.a.d.menu static by applying some custom CSS.

<style type="text/css" >
.fixed
{
	/* Mozilla, Opera, Safari and IE 7 */
	position:fixed !important;
	top:100px;
	left:150px;
	
	/* Internet Explorer 5.5/6 only */
	_position:absolute !important;
	_top:expression(eval(100 + document.documentElement.scrollTop? document.documentElement.scrollTop : document.body.scrollTop) + "px");
	_left:expression(eval(150 + document.documentElement.scrollLeft? document.documentElement.scrollLeft : document.body.scrollLeft ) + "px");
}
<style>
<RadMenu runat="server" ID="RadMenu1" CssClass="fixed" />