Technical note 1: SPWS will continue to respond to requests for about 5 seconds or so. This means you can insert any resources into the final "good bye" page - i.e. graphics, sounds, scripts and stylesheets.
Technical note 2: This "goodbye" functionality is triggered by visiting any resource that has "spws-terminate-and-release-cd" in the virtual path or name of the resource, so you can put such page anywhere on your CDROM.