Firefox not reading IE conditional statement as a comment Options

[Fireater989]

I chose to redirect users using IE to another webpage asking them to upgrade to another browser. The only way to do this without using JS is through IE conditional statements. I won't use a meta refresh, for obvious reasons. I can't use .htaccess because there's no way to use conditional statements with that. I decided on a php script because my page was already php.
My website is http://spotlight.isgreat.org/
I inserted the script via php include so it shows up as regular html. Here's the script that I put in the head tag:
<!--[if IE]>
<?
header( "Location: http://www.spotlight.isgreat.org/ie.html" );
exit(0);
?>
<![endif]-->
These particular statements trigger on all versions of IE and all other browsers should treat it as a comment, however, Firefox redirects, every time. So, it triggers in IE, as it should, and FF, as it shouldn't, and doesn't trigger in Chrome, as it should, and Safari, as it should.
Sooooooo, Why is this happening in Firefox?

I feel like there is a simple answer staring me in the face...

This post has been edited by Fireater989: Aug 8 2010, 01:33 PM