I have adapted my HttpActivityBehaviourImpl in order to add some Authorization header. It all works fine. I did not have to adjust the HttpTask at all. Now I am trying to also change the flowable designer to be able to inject this flowable field httpActivityBehaviorClass. In order to do this I believe we need to add some BpmnJsonConverter. Is it possible to do this in some dynamic way without have to change the source code. Add a new MyCustomHttpJsonConverter or something? And then register it?