You just need to make sure in both your app and the loaded swf that when the concrete Facade's getInstance method is called you pass in some string. In the app you might say
and in the swf you might say
Remember that your concrete facades extend Facade where the multiton instances are kept. So while they may be different subclasses, every Facade in the system must have a unique multiton key. So if you're just calling getInstance in both places with a null string then you're actually ending up with the same Facade because the second call didn't create one, it returned the one mapped to the null-string multiton key which was created by the previous call.