Lamborghini Countach LP500S setbelts?

I know that some companies make seat belts for 1/12 scale RACE cars but what about for street cars? I'd like them for my Otaki/Doyusha Lambo? I know that a few members are building/planning this kit. Let me know what you did.

At 1/12th scale you could quite easily make the hardware yourself out of plastic card, wire, etc. I used to do that before the advent of the internet and aftermarket stuff.