Problem solved!!
I saw someone else on this forum who posted a movie with the very same problem as my car had!
Maybe this is helpfull for him to:
The problem was the oil filler hose... When this gets older the plastic gets hard... My guess is that, when I replaced the AOS, the tube broke when I removed it from the oil filler tube on the engine..
There's a ribbed part in the hpse where it bends... there was a crack in between the ribs.. When the engine was at idle, the tear was closed and the vacuum under the oil filler cap was good, but when the car accellerates the engine somewhat tilts over and opened up the crack. With this, the vacuum dropped and the AOS stopped working, resulting in huge clouds of smoke.
I'm happy I found the problem and the repair only costed 30 euros!
