Hi,
The Send user notification process action is a System flow action and cannot Open documents for users for example. With the current implementation we are unable to do otherwise. When Universal GUI and Indicium support Deep links, then we can take the next step with notifying users and helping them get to the correct spot in the application.
In Web GUI, the only way I can think of currently is as you have specified:
"A badge in combination with a tsf_send_message does indeed work to notify the user his task is finished.”
It is only a normal message and the message options cannot be used to let the user navigate to somewhere; it can only be closed.
Does that answers all questions? 😄