There isn't really a rear view camera at all...There's an orbiting camera which goes all around the car (controlled by mouse) and a few others but none that just looks behind. This would be a good camera view to add, however. Then players could switch to it with a button or key.
.ize, the view you want already exists. You are probably using the Chase (rigid) view instead of the Chase (loose) view. I believe they default to F3 for the rigid one and F4 for the loose one. Try pressing F4!