ActivationConfig of MDB and ActivationSpec in WebSphere AS 7

Question

I'm currently developing a small EJB 3 application for WebSphere AS 7 with WebSphere-MQSeries. It's a very simple app that mainly consists of one MDB listening on a queue, convert the incoming messages and write the extracted data into a db. I've finally got up it and running, but I'm a bit confused regarding ActivationConfig annotations in the code, the ibm-ejb-jar-bnd.xml and the activation spec in WAS itself. My main question is, why do I need ALL of them? Why should/could I specify things like the queue name or destinaton type via annotation (@ActivationConfigProperty) when I still need a activation spec in WAS where I also specify the destination e.g. Queue-Name? I addition I also need a binding via an xml file? Is that right? Is it also possible to specify the activationspec-name via annotation and thus get rid of the xml binding file? Can I avoid creating the activation spec in WAS?

Hope someone can clarify things, thanks.