After several unanswered emails to Zalman about the non-working touchscreen in Vista, i contacted eGalax today, the manufacturers of the touchscreen.
I explained the non-existing support from Zalman, and asked them if they had a firmware update for the touchscreen, since that was what seemed needed to make it work under Vista.
Within 10 hours i received a reply from eGalax, including a driver for Vista 64.
I started setup, it automatically uninstalled the already installed touchkit.
After a reboot i ran setup again and it finished allowing me to calibrate the screen.
And this time..... IT WORKED!!!!!
The current driver doesn't support the beep-on-touch yet, that's a microsoft-issue that will probably be fixed in later versions.
Software can be downloaded from my ftp-server as-is, with no warranty or support whatsoever ofcourse ftp://hd160xtavs:firstname.lastname@example.org
Big thanks to Albert @ Egalax for this fast reply and finally a working touchscreen in Vista 64.
I'm back to enjoying my WORKING HTPC,