The way I understand it you are looking more for the visual side of the problem... which due to being pressed will mostly be covered by the players finger...
By scaling the image down vertically - with a perspective touch - and adding a darker layer on top as well as altering the objects shadow you can create the effect of a pedal being pushed down.
Comments
have a rule in the pedal when touch is pressed
-change image to pressed pedal image
then open up the otherwise section of the rule and put a change image behavior in there as well except have that one change to the regular pedal image
By scaling the image down vertically - with a perspective touch - and adding a darker layer on top as well as altering the objects shadow you can create the effect of a pedal being pushed down.
You are such a great help around here. Highly commendable!
Mike