Mouse listener on a covered area?

I´m doing an image gallery where I need to add an event listener on an area that is being covered by an externally loaded swf that in turn, completely covers the area I want the event listener to react on.

So my question is, how can I remove the event listener on the object that covers the area I want to use as a listener, even though its being covered?

I read about a way to do just that here, but I just cant find it again.

Any help in this matter is, like always, greatly appreciated

Regards
/rundevo