Try this vehicle-cam script, it's pretty much the same as snYpir's although slightly different.
;--Vehicle-cam----------------------------------------------------------
vehiclecamstop = false
#loop
_cam = "camera" camcreate [0,0,0]
_cam cameraeffect ["internal", "front"]
_cam camsettarget Car
_cam camsetrelpos [1, -6, 1.5]
#commit
_cam camcommit 0
_cam camsettarget Car
_cam camcommit 0
~0.01
? NOT(vehiclecamstop) : goto "loop"
_cam cameraeffect ["terminate", "back"]
camdestroy _cam
;------------------------------------------------------------------
Just change the 'Car' to the name of the vehicle u want to target and u can change the X, Y, Z co-ordinates to determine where u want the cam to be in relation to the vehicle.
U will need to set a trigger where u want the cam to end with vehiclecamstop = true in the 'on activation' field and this in the condition field to return to normal play. If the vehicle that is going to activate the trigger is west then a west present trigger is needed obviously.