static function connect()
 {
     $opts = array('trace' => true, 'encoding' => 'ISO-8859-1', 'cache_wsdl' => WSDL_CACHE_NONE);
     //$opts = array('trace' => true, 'encoding'=>'ISO-8859-1', 'cache_wsdl' => WSDL_CACHE_NONE, 'local_cert' => './servidor.cer');
     $wsdl_url = "https://www.aespd.es:443/agenciapd/axis/SolicitudService?wsdl";
     try {
         xmlResponse::$client = new SoapClient($wsdl_url, $opts);
         return array('result' => 'ok');
     } catch (SOAPFault $e) {
         return array('result' => 'fail', 'message' => $e);
     }
 }