I wouldn't have thought it was a particularly easy retrofit, but I suppose if you've got all the required parts it just comes down to coding with Star?
Hi, As Whitenemesis said I have done it on my CLS55. Not a hard retro fit, but the parts can be expensive if buying new, or if trying to get them second hand you could have a problem as most breakers haven't a clue what it is let alone get the part off undamaged etc.