>> You can do this testing by creating the scoped client context to contain a EJB receiver with a specific user credential." -> is there any way to do that? I wasn't able to find out how to get hold of associated receivers and retrieve credential info from them. I lack some documentation, had to go through the code. If you could point be at least a bit, I would be very grateful.

You won't have to iterate over the receivers. What needs to be done is use a scoped EJB client context by passing it a specific user (which is different that the one configured in the jboss-ejb-client.properties) to connect to the receiver at 4447 port. Then the server side bean would check if the invoked caller prinicpal is the one that was used to connect using the scoped EJB client context.