* <li>Invocations accumulated as Request subtypes passed to {@link #addInvocation}.
* </ul>
*/
public String makePayload() {
// Get the factory from the runtime-specific holder.
MessageFactory f = MessageFactoryHolder.FACTORY;
List<OperationMessage> operations = makePayloadOperations();
List<InvocationMessage> invocationMessages = makePayloadInvocations();
// Create the outer envelope message
AutoBean<RequestMessage> bean = f.request();
RequestMessage requestMessage = bean.as();
requestMessage.setRequestFactory(getRequestFactory().getFactoryTypeToken());
if (!invocationMessages.isEmpty()) {
requestMessage.setInvocations(invocationMessages);
}