If I talk about using a serviceInvoker I mean org.jboss.soa.esb.client.ServiceInvoker as used in many quickstarts. You can create your own action and implement this like:
ServiceInvoker invoker = new ServiceInvoker(new Service("category", "service"));
Message recievedMessage = invoker.deliverSync(messageToDeliver, timeoutMillis);
Regards,
Hans