If I remember right while transferring my car from UAE to Qatar, some 5 yrs back, I had to take out the transit insurance for a short period at a small amount (some Dh.100/-, not sure though) before the car can be released for export and can get the export plates. Not sure what it is like now or if it is any different otherwise here. In any case, if the amount is small it can either be absorbed by you or the buyer can reimburse it to you. However, logically seems the buyer needs to take out a transit insurance either separately or may be the one taken out by you can be transferred in his name. I would suggest to visit the traffic deptt. to get the first hand info to avoid any inconvenience at the last moment. Cheers!