Thanks, Jim, for providing that link to the accessories catalog. I see that there is a hitch listed in the lower right corner of that page (3D0 092 155). Sometimes the European part numbers are valid in North America, even though the product is not advertised, so it might be worth checking with a local dealer.
There are some potential problems, though: The size of the ball used in Europe is different (smaller) than the ball size used in North America. Also, from the look of that hitch, it appears that the hook assembly (ball) would need to be removed, and some custom work done to attach a bike rack.
Sadly, the purpose-specific bike rack shown on the left hand side of that same page can't be used with our North American Phaetons, because they do not have the roof attach points needed to install the basic rack brackets.
I got a feeling you might be out of luck on this one, Lee. But - welcome to our forum anyway - hope we can come up with a better answer for you on your next question!