Hi Hermann, if you need assistance for the homologation in Switzerland, you may contact also Normando Ruggiero in Buttwil, Switzerland, at Novidem ag (
http://www.novidem.ch/novidem-classics/, info(at)novidem.ch), they have some AC Mk IV among there customer's cars and seem comfortable with their homologation, maintenance and upgrades.
In any case, if you have owned the car for more than 6 months outside of Switzerland, you can import ist as Übersiedlungsgut (migrant or household effect) and homologation is quite straightforward, my wife did the same with her car from Dubai, eventhough the model was not available in CH.