1. ID is needed by the traffic department to identify you only, and you can present your passport with visa page, no issue.
2. If not then take a photo copy of your license and attach with it, if still not then
3. Go to Roama Car showroom at street 10 in industrial area (both the buyer and seller), show them the above papers, pay them Qar. 200 transfer fee plus 100 being their service fee, and that's all, they would arrange the transfer by their person and the buyer can collect the new car RP in his name from them, the next day evening.