Guy,
We actually got that to work as we wanted it to today. I don't know if you're still interested in a solution like that anymore.
Our solution was to create a custom field (called Application) as a reference to an Object of type Risk. We created this custom field at the Request object level.
Our Custom Action form (that creates software change requests) references the Application field on the form. In one of the Set Actions on the custom action, we update NewObject1.Application with the Application variable from the user form.
So far that's worked and isn't limited by a Social license...