Wirewheel, Ray,
thank you for your information. It seems to me as if both grease nipples feed the same area. Upper nipple trough the kingpin and a little bore from inside and the lower nipple at the stub axle direct into the area between the bronze bushes. The drawing in the parts book gives that impression to me.
There were some discussions in the past about using oil on the upper and grease on the lower nipple, that would also only make sense if they were connected.
I'll ask my dealer next time. Again, thanks for the help,

Regards

Ex-Roadster 3.7, now P6