VP has all the modeling components, why not flow charting
Use business process diagram? It has start, end, task, decision (gateway), flow, data and lot of variations. If needed, you can mix other shapes too like actor from model tree. I don’t understand what else would you like to have from “flow charting”.
I know this is an old thread, but I hadn’t seen this before yet.
Another good choice is the activity diagram as being used within UML.