public function toXml()
    {
        if (is_string($this->wsdlXmlSource) && $this->wsdlXmlSource != '') {
            return $this->wsdlXmlSource;
        } else {
            $this->prepareDom();
            $this->prepareReflection();
            $this->prepare();
            $this->wsdlXmlSource = $this->dom->saveXML();
            return $this->wsdlXmlSource;
        }
    }