Hi, guys!
Unfortunately for those who were among the first to perchase a ProfiTX - like me - the problem ist well known. You might replace them yourself (d.i.y.), the neccessary key-spider you get at the MPX-service. But it involves quite a lot of work because you have to disassemble almost the complete transmitter. I got my new keys when I sent the transmitter in for a different problem. You have got to wet their eyes a bit (that definitely sounds German!) a bit and they will do it on a goodwill basis as HG73 has said.
Here I have to praise the MPX-service again: sent in on monday - back on friday - saturday on the field - what can you want more. Alas, I don't know if that is true for our friends on the isles or elsewhere abroad Germany.
so long
profimc