To be honest Steve, your not going to get the glowing style mac buttons unless its with mouse over.
If you do want to try animating the System button image, make sure you have multiples of 5.
What I mean by this is the normal 5 image states plus the 5 or 10 frames for animation. Try not to use the last frame as I have found you tend to get a lot of glitches showing, but this might be down to my graphics card.
The other thing I have noticed when using animation is that the pressed image is overridden by the animation.
Mitch