Installing a door gasket
 

Our 2001 300m is leaking when it rains. We had the dealer install a new door/frame gasket on the drivers side door and it still leaks. We now believe that the drivers side rear door needs it too as it's only that side of the car that is still getting wet.
Does one need any special tools to install that gasket? it looks as if, it's just a matter of patience and making sure it gets punched on right.

Can anyone shed some light on installing on these gaskets.