private function addService($serviceName)
    {
        $this->addToDebug("Adding service: '$serviceName'");
        //create service
        $serviceTag = $this->addElement('wsdl:service', $this->definitions);
        $serviceTag->setAttribute('name', $serviceName);

            //port tag
            $portTag = $this->addElement('wsdl:port', $serviceTag);
        $portTag->setAttribute('name', $serviceName.'Port');
        $portTag->setAttribute('binding', 'tns:'.$serviceName.'Binding');

                //address tag
                $addressTag = $this->addElement('soap:address', $portTag);
        $addressTag->setAttribute('location', $this->url);

        //keep a reference
        $this->serviceTags[$serviceName] = $serviceTag;
        //and return
        return $serviceTag;
    }