How to setup PCG Flow Rule Process flow with Business Event subscription type?
When should Business Events be used?
The latest user guide does not provide ay information on this functionality of Flow rules.
You should find it's usage noted in the new PCG user guide on page 3-26 under the heading "Configuring Workflow/Event Rules". This way you can have a Flow Rule call a business event component or a workflow. This would be kicked off within a process flow as one of the steps.