public function addService($name, $portName, $binding, $location)
    {
        $service = $this->dom->createElement('service');
        $service->setAttribute('name', $name);

        $port = $this->dom->createElement('port');
        $port->setAttribute('name', $portName);
        $port->setAttribute('binding', $binding);

        $soapAddress = $this->dom->createElement('soap:address');
        $soapAddress->setAttribute('location', $location);

        $port->appendChild($soapAddress);
        $service->appendChild($port);

        $this->wsdl->appendChild($service);

        return $service;
    }