JCA JMS outbound does not work if the inbound gateway is anything other than JCA inbound. For example, if you take the jca outbound quickstart and change the inbound gateway to file, then the outbound message is not available in the destination queue. I suspect this is due to the fact that there is no transaction management in place if JCA inbound is not used and the outbound flow is expecting another participant to commit the transaction.

See the forum thread for nitty gritty details.