private function buildSoapClient() {
		$header = $this->buildAuthHeader();

		if($this->isTest())
			$location = self::DHL_SANDBOX_URL;
		else
			$location = self::DHL_PRODUCTION_URL;

		$auth_params = array(
			'login' => $this->getCredentials()->getApiUser(),
			'password' => $this->getCredentials()->getApiPassword(),
			'location' => $location,
			'trace' => 1
		);

		$this->setSoapClient(new SoapClient($this->getAPIUrl(), $auth_params));
		$this->getSoapClient()->__setSoapHeaders($header);
	}