Can you select a state for a button via AS3?

How do you select a state of a button (movie clip with Flasheff2 on it) via AS3 code?

On certain frames, I want to make sure the state is UP and not the selected state. I just have one button.

Thanks,

Simon

The states are given by the mouse, so, for example,you cannot set on frame 2 the state over when the state for the mouse is selected down.