How to load a Menu dynamically associated with a MenuButton

I thought you would of been able to attachPress function to a MenuButton in order to load the associated Menu prior to it being displayed. The only listener I've been able to attach is the selected listener. So am I using the wrong attachXXXX function or does one have to override the MenuButton press listener, and if so how does one call the super press function (or default MenuButton function) after one has initialized the popup menu? An example would be appreciated.

PS - Since the Menu and MenuItem are depreciated in commons, does the MenuButton still work with the js in unified package?

Thx - Joe