well, I think I'm a little closer :).
It seems it's up to the client to handle the async stuff, either by starting the CommandExecutorThread (e.g. by running the jbpm webapp, or inside a custom app), or by subscribing a MessageListener to the message queue, in case one choses to use org.jbpm.msg.jms.JmsMessageServiceFactoryImpl.
I haven't found the JMS counterpart of CommandExecutorThread, is there any MessageListener?, in case I have to implement it, I should do the same CommandExecutorThread stuff plus the JMS handling, right?.
Am I in the right direction? any help is highly appreciated
There is not (yet) any JMS counterpart of the CommandExecutorThread. In fact if you use JMS, you should not have any separate CommandExecutorThread. MDB's have been invented to do this job... But again, you should create this MDB yourself, we do not provide one at this time.