private function addBindingOperations($operation, $input = false, $output = false)
    {
        $el = $this->dom->createElement('wsdl:operation');
        $el->setAttribute('name', $operation);
        
        $soapOperation = $this->dom->createElement('soap:operation');
        $soapOperation->setAttribute('soapAction', $this->wsdlTargetNamespace."/".$operation);
        $el->appendChild($soapOperation);
        
        if ($input === true) {
            $inp = $this->dom->createElement('wsdl:input');
            $body = $this->dom->createElement('soap:body');
            $body->setAttribute('use', 'literal');
            $inp->appendChild($body);
            $el->appendChild($inp);
        }
        
        if ($output === true) {
            $out = $this->dom->createElement('wsdl:output');
            $body = $this->dom->createElement('soap:body');
            $body->setAttribute('use', 'literal');
            $out->appendChild($body);
            $el->appendChild($out);
        }
        
        $this->wsBinding->appendChild($el);
    }