you wrote "Any assistance", so i would solve it with java script and php eg
<script type="text/javascript">
setTimeout("window.location.href='http://somewhere,com/<?echo $username;?>/';",100);
</script>
it would work, but i don't know if you wanna use JS in rder to do this if you have the opportunity with manpulating the header as you gave your example code. But if you want give it a try.
regards ali