Hi @RafalO,
Please check the function of the AA command. As I understand, it is used to add an alternative to a list of data id’s that is used as a substitute for data id’s that are found to be unknown to the device.
As an example: if the thermostat sends data-id 99 and the boiler responds that 99 is an unknown data-id, then the next time this message is sent by the thermostat, the OTGW will substitute it by a data-id from the stored list of alternatives.
So AA=71 by itself doesn’t do anything other than adding 71 to the list of alternatives. Confirmed by the AA:71 response. It then relies on some unknown message to be sent by (for example) a thermostat to be able to substitute this message with one of the id’s from the list of alternatives. So as long as no message is initiated and sent to the boiler (or in your case the Brink), there is nothing there for the OTGW to replace.
I am not sure how this should work, but you will need something that initiates the messages to the Brink device. WIth a thermostat/boiler setup this would logically be the thermostat. In your case it would have to be some rule from openHAB or the OTGW device itself (using PM ?) that triggers messages. But that won’t happen automatically from the AA list.