Accessing MC's from class not created by AS

Looks like very simple but i cant find solution even after reading Display Programming Section help files in AS3 help.

I need to access a movieclip, which i dragged and dropped to the stage, from class.If i checked how many childrens stage has, then its 2, 1 is MainTimeline and other is movieclip i created from that class using AS3. Where the heck is the movieclip which i dragged and dropped to the stage.

Need help and thank you for reading.