How do i target an iframe from flash....?

I have a windows media player within an iframe that is streaming a video. I need to be able to target the player from within flash and tell it to play a new video. The video player seems to have an ID tag of <OBJECT ID=“MediaPlayer1”

But how do I target it from flash and tell it to play a new video? Can you help me?

Thanks.

IOBJECT ID=“MediaPlayer1”
mms://66.180.203.186/song1/ —this is the loaction of the new video I want to play.

Also, …the button I am using in flash is in a movie, loaded into a main movie.