Communication between AS 1.0 and AS 3.0

Hello Friends,

I am having a small doubt in flash. It was a communication problem between flash cs3 and flash mx 2004.

I am using flash cs3, I am loading an external swf file into my application(the loaded file is in mx2004 format, in which I have a button). Now on clicking on that button i want to call a method which is there inside flash cs3.

How to do this ? can anyone answer my ques asap. Its very urgent

Regards,
Rajesh