Tiptronic selector button.

The button on the right of the selector knob has been loose but functioning for a long time but today it popped off and I see there are a couple of broken plastic bits sitting inside the knob cavity. A new knob assembly is around 150 quid, so has anyone been successful in doing a repair to make the button work? Is its function solely to push in the plastic plunger with a steel pin in the end? I have pushed the button back in place and its working but likely to drop out again .

Any helpful advice much appreciated.

Cheers..

March 2005 Skoda Superb 1.9tdi Auto .