Artemis currently does not support transactional acknowledgements:

Message acknowledgements are not transactional. The ACK frame can not be part of a transaction (it will be ignored if its transaction header is set).

The STOMP 1.2 specification contains:

Optionally, a transaction header MAY be specified, indicating that the message acknowledgment SHOULD be part of the named transaction.

And other brokers (such as ActiveMQ 5.x) do support transactional acknowledgements.

Artemis should support them too.