R – How to get the background colour of a loaded swf

When you load in an external swf at runtime is there any way to get the background colour of the swf? – That is the stage background colour.
The loaded swf is uploaded by users, who may or may not know the correct colour.
I know that normally this is specified in the HTML code to embed a swf, but if you run a swf in the standalone player it will display the correct colour, so the information should be there somewhere.
What I want to do is to create a background behind the loaded swf, so it will display like intended.

EDIT:
I would prefer a client side solution if it is at all possible. If not the server side is .net based.