Place ont the map the vehicle you want to try, some plastic barrels on the left and some metal barrels on the right, like this :
http://image.noelshack.com/fichiers/2014/18/1398976072-arma3-2014-05-01-22-27-05-89.png
Then preview and move the vehicle in order to see the bug.
(exemple : put the truck really close from the blue barrels, and notice that you see metal barrels on the left mirror.)