The aero button can be found in this thread:
viewtopic.php?f=18&t=3208To edit it, simply use any image editing software
It should be noted that the one included in classic shell is technically animated (see the last image in that thread) However you will get much of the same with the second button in that thread. (just with less smooth transitions between states)
The animated one you have to be careful to not change the top row of pixels any, or it will destroy the animation sequence.
To apply it, simply select 'custom' and find the modified version on your system (Note: put the file somewhere it wont get removed, because classic shell links to it, rather than storing its own 'internal' copy)