Can I work in Classes like this?

Hi I have a Main Class, a Menu Class, a Cuboid Class and a KeyPress Class. I am using away3d v4 with Flash CS6. So Main set up the view and KeyPress is called. On keyDown ‘m’, Menu.initmenu() is called and this all works just fine. Is it possible to use addChild or what variant should it be. Am having trouble in identifying the path for adding the movieclip to the stage/view/scene. Will post the code in a short while. Regards FJW