Я использовал "fopen", и он работает.
//You can use 'POST','GET','PUT' or 'DELETE'
$opts = array(
'http'=>array(
'method'=>'POST',
'header'=>"Content-Type: text/xml\r\n" .
$auth."\r\n",
'content'=>$xml
)
);
$context = stream_context_create($opts);
/* Sends an http request to www.example.com
with additional headers shown above */
$fp = fopen($url, 'r', false, $context);
fpassthru($fp);
fclose($fp);