(Of course, the background-position: changes with whichever sprite it's loading.)
I did try changing this before, too, but I figured maybe I made a mistake, so I tried again. XD I didn't have any lick.
EDIT: Whoops... I was wrong! I didn't have a space before the !important bit. O_O
It works now, thanks!
I just tried it myself. It worked just edit the css file itself. Download the file from your server at clientscript/ckeditor/skins/kama/toolbar.css and just add: