there's a nice program called Microangelo, the newest version is 5.5. and is about 4 megs
With this you can do all sorts of changes to your icaons, even make the bakground for the icons transparent.
When you install it, run it then choose the icon you want to change, then right click and choose appearance for the little menu, then all you do is go to the directory where you have the viao icons and choose the icon you want. Do this for all the icons you want to change....
you can get the program here
http://www.impactsoftware.com, its a trial version but im sure you can get the full one elsewhere