private function plainXML($xmlRequest)
    {
        $envelope = new DOMDocument();
        $envelope->loadXML(
            '<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
		    <soapenv:Body></soapenv:Body>
		</soapenv:Envelope>'
        );

        $envelope->encoding = 'UTF-8';
        $envelope->version = '1.0';
        $xmlRequestType = $xmlRequest->documentElement->localName;
        $xmlRequestTypeNode = $xmlRequest->getElementsByTagName($xmlRequestType)->item(0);
        $xmlRequestTypeNode = $envelope->importNode($xmlRequestTypeNode, true);

        $envelope->getElementsByTagName('Body')->item(0)->appendChild($xmlRequestTypeNode);

        return $envelope->saveXML();
    }