Gustavo,
Whenever I have subscription issues, I change the Send Port subscription to work on BTS.ReceivePortName, re-enlist but do not start the Send Port.
Run a message through and it will suspend (resumable); open the message in the Admin Console and look at the context properties for the MessageType – copy and paste the proptery value and use that in your BTS.MessageType filter (remembering to take the receive port name filter off).
Rgds, Nick.