[Simon Lloyd]

Unfortunately you'll probebly not get your answer here as it's not a plugin developed here or to do with any core vbulletin files, however, they are showing you that they would use echo to enter the sessions has so i assume you'd want something like

PHP Code:

$idhash = md5($_SERVER['HTTP_USER_AGENT'] . $vbuser['userid']);
$sessionhash = md5($now . request_uri() . $idhash . $_SERVER['REMOTE_ADDR'] );
$('#file_upload).uploadify({ 
    // Your normal options here 
    formData : { '<?php echo $sessionhash;?>' : '<?php echo $idhash;?>' } 
});