How to use MQTT publish with InTouch Stand alone?

A customer would like to publish data from their InTouch Tags also to a MQTT Broker.
There is now the MQTT Publisher functionality in the Driver, but I believe this only works for Application Server.

What would be the best way to create the same functionality for InTouch?
So an existing InTouch application and publish tag data to a MQTT Broker. (also data that is already IO bound to another driver)