protected OMElement invokeDataServiceOperation(String opName, OMElement soapBody, MEP mep) throws AxisFault, XMLStreamException {
MessageReceiver msgReceiver;
if (mep == MEP.INOUT) {
msgReceiver = new DBInOutMessageReceiver();
} else {
msgReceiver = new DBInOnlyMessageReceiver();
}
MessageContext msgCtx = buildMessageContext(opName);
SOAPFactory soapFactory = new SOAP12Factory();
SOAPEnvelope env = soapFactory.getDefaultEnvelope();