W107 installing antenna rubber gromet--how?

[dmotl]

Have an 85 sl280 with power anntenna. The rubber gromet rotted out so I got a new one from Phil. Now the fun has begun.

First of all the grommet has a slope to it. Does the slope point to the front or rear of the car?

How do you install it? it does not slip in from the top over the antenna.
Further the main sealing part of the grommet has a slit indicating that is to cover the sheet metal on both sides. I do not know how that is possible to install from the top pushing down or from the inside of the trunk pushing it up.

Hoping someone has done this and can offer help.

Thanks

Dan