Hello Vincent,
Thanks very much for the interest.
Touch-screen drivers emulate mouse clicks, so from Hauptwerk's point of view a touch-screen 'touch' is no different to a mouse click. All editions of Hauptwerk (including the Free Edition) support mouse clicks and a single touch-screen. However, only the Advanced Edition allows you to use Hauptwerk across multiple touch-screens (e.g. with different virtual stop jambs shown on each of the screens).