Transition with a mandatory action

[Mark Lawson]

I want a transition (from State A to State B) which reveals a screen with YES/NO radio buttons and will go back to A if the radio button is not set to NO, it will only move on the B if the YES button is selected. 

When the Transition is first activated, the radio button must be made to sit in the NO position so that the YES/NO decision is made at the point of the transition and not before.

[Jeremy Gaudet]

You can put a validator on the transition such that a field has to be a certain value.  If they select NO, however, it will not cancel the transition, it will show an error indicating that the transition is only available if they select YES; at that point, they either have to cancel the transition (you can mention that in the message) or else change the selection to YES.  Not quite what you are looking for, but I think it's pretty close.

A possible alternative would be to add javascript to the page such that clicking on the transition button from the screen performs a cancel if NO and the transition if YES.