How to create Activity w/ Parameter Nodes, and call it from another Activity

UML
1

Howdy–

Guys, my understanding of UML still has a ways to go, and my I’m still a bit new to VP, so please bear with me. I would like to accomplish the following:

  1. Create, on its own Diagram, an Activity called SUBACT, with parameters IN (input) and OUT (output).
  2. Call SUBACT within a another Activity called ACT, with the IN and OUT nodes available for object flows.

Very basic stuff in any programming language (my home turf is LabView). Currently, I’m stumped right out of the gate, as I can’t add Activity Parameter Nodes to my SUBACT diagram (I tried adding them at the edges). What am I missing there?

Beyond that, I’m also confused about the steps to take for calling my sub-activity. I can see that, within ACT, I might place an Action, set the Type as Call Behavior Action, then select the Behavior from the list. But my SUBACT doesn’t show up on that list. Further, this approach seems like in would not automatically keep up with SUBACT’s IN and OUT as nodes on ACT’s diagram. Is Call Behavior Action even the correct way to do what I’m attempting?

Thanks all, for your patience, and any wisdom you can spare.