To
edit scale constraint channels with the Channel Box
In the scene, select the constrained
object.
In the Channel Box,
the following channels are listed for the scale constraint:
Click the name of the channel you want
to edit.
In your scene, -click
and move the mouse to the left or right. By moving the mouse, you
interactively change the value of the selected channel. As you move
the mouse, note that pressing the key gives
you finer control, and pressing the key
gives you less control.