Hello and thanks for the answer, even though it did not help very much.
I have spend an hour or two fiddling with this and came to conclusion that it was in fact the brakesystem, but not the switch on the pedal which caused havoc with my warning lights.
After taking the brakeswitch out and meassuring the continuity on the switch, I found it was in good condition. I figured out that a faulty brakeswitch would most probably also would make the relay for releasing the tiptronic gearstick locked(red pedal light beside the stick), driver not beeing in able to operate the stick.(No brakelight, ESP and ABS warning lights and locked gearstick is a sure sign of faulty brakeswitch folks)
It was actually fuse no #13(brakes, checked it visually twice before meassuring it) that fooled me. Not easy to see that it was broken but meassured continuity, found it was gone to ****, changet it and ....voila
I think,but I am not sure, faulty ABS sensor would still let the cruisecontrol operate???
Hopefully this can help someone else also as I have seen many postings about this problem....