Can you post an example of the response that you are trying to process, exactly which chunk of it you want to be returned to the data action, and what you have tried so far? Feel free to redact any sensitive parts of the reponse.
Good news for me, finally i found right approach to do what i need
I was trying to call data action from workflow to get data of the conversation (wich triggered workllow). Going little bit deeper i noticed the triggers where sending the info i need trough "in" parameters to the workflow, so i dont need to create the action data because the trigger is sending it yet.
I will let pending the stuff about velocity macros until i need. It is pretty hard to understand and create right syntax, so, let´s see on the future (hope far...)