Feeding Windows Media Player with PHP

I'm trying to develop a playlist in Windows Media Player where the audio is fed through PHP for security reasons. It works fine in Winamp and iTunes, but Windows Media can't play the file.

We're trying this header with PHP:
header("Pragma: public");
header("Expires: 0");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header("Cache-Control: private",false);
header("Content-type: application/force-download");
header('Content-Transfer-Encoding: Binary' ); // added
header("Content-Disposition: attachment; filename=\"".basename($FILE)."\";" );
readfile ( $URL );

And so far we get it where it DOWNLOADS the file 100% and then starts playing. Is there anyway to have it start playing while its downloading, like iTunes and Winamp does

Thanks for any help!