// callback method
// Relaxing this assumption, however, does not seem to be trivial,
// it may depend on knowledge
// of what actual callback method was invoked by the service at the
// other end
Operation callbackOperation = findCallbackOperation();
Axis2CallbackInvocationHandler invocationHandler =
new Axis2CallbackInvocationHandler(inboundWire);
Axis2ReferenceCallbackTargetInvoker callbackInvoker =
new Axis2ReferenceCallbackTargetInvoker(callbackOperation, inboundWire, invocationHandler);
invoker.setCallbackTargetInvoker(callbackInvoker);