We found the first waypoint with the box containing the (laminated) sheets with the instructions on how to proceed further without too many problems -- but we took a (short) trip back to the car to get an umbrella, because the rain had started up again.
But the second waypoint remained out of our grasp. We must have spent half an hour walking around in the area the GPSr pointed to as the spot. We must have seen the underside of every tree, but we could not find the promised hint... So finally we decided to give up on this one for today.
On our way back, we took a detour towards Hersendeler, which we had now solved to get the right coordinates. But again, we were unable to locate the cache. According to the GPSr, the cache should be located... right in the middle of the pond.
Muttering dire curses under our breath, we went home, without a single find to log...
When we keyed the coordinates into Google Maps, we found that the GPSr had been tens of meters off! Maybe someone in the US had been twiddling with the knob to distort the GPS signal a little too enthousiastic, or perhaps the sattelites were in such a constellation that minimised correct triangulation... Perhaps we'll never know.
Maybe next time, we'll check the reception at home -- if it's mispointing wildly, it's nice to know before travelling to the cache location.