A number of years ago, one of the buttons on my Xantia fob broke off. It damaged the circuit board so I could not try replacing with a switch available on ebay.
I recently discovered a company called "irefab" and sent my damaged fob to him. Not only has he repaired it in few days, but made a video showing just how much work he did. It looks easy, but without any of the gear its impossible to achieve his high standard
For those of you with similar issues I can 100% recommend his work
Thinking outside of the box is better than sitting in a dark one.