Kurzeitmarke- Entry Vehicle letter

Hello, I have the following problem. I would like to introduce a vehicle to Belgium, which I bought privately in Germany. The person I bought the vehicle from did not register this vehicle. Therefore, on the vehicle letter is still the previous owner who leased the vehicle. The Belgian customs authorities must receive proof that VAT has been paid for this vehicle in Germany. no information about this vehicle. The customs has informed me as a possibility to allow the vehicle in Germany so that a private person is registered in the vehicle letter and the vehicle is then no longer subject to VAT as a “right” private purchase. Can anyone give me information about whether a new vehicle letter is issued on the authorised person when applying for a short-term registration mark? Anyone sees another possibility- possible seasonal registration,… and what costs Thank you so much for your efforts, Greetings Toto.