Looking for old trailer hitch documentation

[Nick-Night]

I need your help, I want to attach a trailer hitch to my Model A Tudor. In order to get this approved by the German TÜV, I need old documents that show a towing capacity for the Model A. As well as a support load. Old documents on towbars would also be good. I don't think there is such a thing, but I'm not giving up hope that someone here still has old documents and prospects.