I've seen, once, in a UK magazine a 1303 that had a Passat rack but there were not technical details of the install.

Steve C had retrofitted a 1303 rack to his 1302, it's not too difficult. Just look at how the rack is mounted in and change all that over to your car from the donor (some welding will be required for the brackets). You'll also need the tie rods and steering shaft. Lastly, there is a "dip" that has to be made in the early frame head to clear the rack in the center.