Pass Variables

So I have a registration script in PHP that does the registration process and then redirects the person to a registration success page. The url looks like this when they're sent there.

Code:

http://DCL/Webgame/Reg_Suc.html?uname=Alzie

When I try to do the following:

Code:

<HTML> <HEAD> <title>Reg Success</title> </HEAD> <BODY> <h1>You've been sucessfully registered <?php echo $_GET['uname'] ?>!</h1> </BODY> </HTML>

It's blank where the uname should be. This is how the URL is constructed:

Code:

header( 'Location: Reg_Suc.html?uname='.$_POST['UNAME'] ) ;

So why isn't Get working here? Also, is there anyway to send data through the POST method using PHP when redirecting?