onReleaseOutside and stage security dependant

In order to solve the missing onReleaseOutside event in AS3, everybody seems to use the stage MOUSE_UP event. However, this is not a solution in the following situation:

movieA.swf loads movieB.swf from a different security domain.
movieB.swf wants to register stage events like MOUSE_UP or MOUSE_LEAVE but trying to access movieB.stage throws a security error because stage is in movieA’s security domain.
Also loading movieB into A’s security domain, or allowing access to movieB’s domain is not an option.

can anyone please suggest a workaround or a way to implement (the taken-for-granted, most loved) onReleaseOutside in AS3?
thank you