Creating Movie clip on button press

Im making a flash game. And Need to have a menu (sized based on what they click, small medium large) referenced from a movieclip, and variables passed to it. Im using CS4/AS2. Is there a function i can put on my button to create a movie clip at a location? Thanks in advance!

You can use the _x & _y properties of a movie clip to set the location.

Whats the code for on(release) to create a movie clip named "medium_menu" and pass variable 1 2 and 3 to it?