Does anyone know of a possible cable route from the trunk through to the cabin on a CLS W219?

I'm planning to fit a magnetic DAB antenna on the roof whose cable will run down the edge of the rear screen into the trunk. The cable will then need to pass through to the passenger compartment some how.

Has anyone discovered an existing path through from the trunk to the cabin before I start pulling trim off and seats out trying to find one??

Thanks, Ian.