Another option could be, in your document class (minimal example)
package
{
import flash.display.MovieClip;
import flash.display.Stage;
public class MainClass extends MovieClip
{
public static var stageRef:Stage;
public function MainClass():void
{
stageRef = stage;
}
}
}
and, to refer to the stage, you could make a new instance of it in your other classes:
public var cur:Stage = MainClass.stageRef;
cur.addChild(self);
or just by
MainClass.stageRef.addChild(self);
Good luck!