Touchscreen screensaver password protect

We are wanting to utilize a group policy that will enforce a password protected screensaver starting after 10 minutes of inactivity on any workstation. The problem arises with a group of users who operate scanners with touchscreens. They do not use their mice or keyboards. Therefore, 10 minutes after they begin work, their screensaver will start and they are required to input their password to unlock it. Is there a way in Windows XP (perhaps via a registry hack) to enable the use of a touchscreen to keep the screensaver from turning on?