Custom Sound APNS

I want to send a push notification with a custom sound, but always I try, I hear only the default message.

my sound is called wil.caf and I have it in my xcode project.

this is my php sript to trigger a push message:

<?php

$message = $_GET["message"];

$deviceToken = $_GET["token"];


$devideToken = dechex ($deviceToken);
// Payload erstellen und JSON codieren

$payload['aps'] = array('alert' => $message, 'badge' => 0, 'sound' => 'default');
$payload = json_encode($payload);
$apnsHost = 'gateway.push.apple.com';

$apnsPort = 2195;

$apnsCert = 'apsDevBundle2.pem';



// Stream erstellen

$streamContext = stream_context_create();

stream_context_set_option($streamContext, 'ssl', 'local_cert', $apnsCert);



$apns = stream_socket_client('ssl://' . $apnsHost . ':' . $apnsPort, $error, $errorString, 2, STREAM_CLIENT_CONNECT, $streamContext);

if ($apns)

{

  // Nachricht erstellen und senden

  $apnsMessage = chr(0) . chr(0) . chr(32) . pack('H*', str_replace(' ', '', $deviceToken)) . chr(0) . chr(strlen($payload)).$payload;

  fwrite($apns, $apnsMessage);



  // Verbindung schliessen

  fclose($apns);

} 

else

{

  echo "Fehler!";

  var_dump($error);

  var_dump($errorString);

}

?>

Can anybody help me?