XML data ok.. but the php file doesnt do the job

Hello

Im trying to do a guestbook. And i can read very well the XML file and show it. The problem is to save the XML after the post.

I have cheked the XML befaure it is send e it is OK. Só my problem must be de part of AS3->PHP->XML file

here is my code in FLASH...

    var urlFicheiroPHP:URLRequest = new URLRequest("mensagens.php");
    urlFicheiroPHP.data = myXML;
    urlFicheiroPHP.contentType = "text/xml";
    urlFicheiroPHP.method = URLRequestMethod.POST;
   
    var loader:URLLoader = new URLLoader();
    loader.load(urlFicheiroPHP);
    loader.addEventListener(Event.COMPLETE, loadOkFicheiroPHP);

Here is my code in PHP

<?php 
if (isset($GLOBALS["HTTP_RAW_POST_DATA"])){ 
    $xml .= $GLOBALS["HTTP_RAW_POST_DATA"]; 
    $file = fopen("messages.xml","wb"); 
    fwrite($file, $xml);
    fclose($file); 
    echo "teste";
} 
?>

HEEEEEEELLLLLLLLLLLPPPPPPPPP!!!!...