HDT Berlina, Help needed.

[LeeoD]

Hi people, Got myself a VS Berlina HDT enhanced wagon. A few months ago I took it up to HDT main office in Smeaton Grange, Sydney. The main man who runs the show named Ben comes out and has a good look at it. He agreed with me that it is definately a car they did years ago, and that he vaguely remembers it because it was a one off green berlina wagon. He asked me what happened to the wheels off it ? Owner got rid of them on Ebay mate, can you believe it ?. He gets on his computer and checks the vin and eng number, double checks it. Turns around and says "sorry mate cant find it on the computer, so I can't give you a certificate of authenticity." I was so dissapointed. Do these guys not have archived paperwork in cardboard boxes lying in a dusty room somewhere ? The previous owners full name was given and I supplied them with the original owners total cost to buy the car off the showroom floor and he drove it straight to HDT when they were located in Revesby, Sydney. Total cost was $67,000.
Where do I stand on this ? My problem is that the previous owner did not bother to get it build plated back in 1995 because he said it was a big rip off to get a plate put on it and he had already spent enough money on it to be upgraded. There has to be records somewhere right ?. I offered to pay for the build plate but was denied. All I want is some kind of plate or certificate from them. No go, not interested. Any suggestions ?