PHP ve SOAP ile dosya yüklemek mümkün mü?

Burada kullanılan PHP kodu:

$post = "a.txt";

$fp = fopen($post, "r");

$client = new SoapClient("http://api.4shared.com/servlet/services/DesktopApp?wsdl");

$id = $client->createUploadSessionKey("user","pass",-1);

$new_id = $client->uploadStartFile("user","pass",-1, "name", 500*1024);         
$dcId = $client->getNewFileDataCenter("user","pass");
$sessKey = $client->createUploadSessionKey("user","pass", -1);
$upload = $client->getUploadFormUrl($dcId, $sessKey);

$res = $client->uploadFinishFile("user","pass", $new_id, $fp);