private function getSoapClient()
    {
        if (null === $this->soapClient) {
            $this->soapClient = new \SoapClient(
                $this->wsdl,
                array(
                    'classmap' => $this->classmap,
                    'user_agent' => 'Mozilla', // the request fails unless a (dummy) user agent is specified
                    'exceptions' => true,
                )
            );
        }

        return $this->soapClient;
    }