Is it possible to fix or replace buttons on the CD player
 

I have a 2011 BMW X5 M, and in the hot sun, on of the programmable buttons on the CD player broke and popped out. It goes back in, and will sit resting in its socket, but the part that allows it to snap in broke. So the button can slide out whenever it feels like it.

I would prefer not to buy an entire head unit (I think they're close to $3000), just to fix this button. Does anyone have any ideas on how I could fix this? Can buttons be removed and swapped if I can locate a donor unit? Thanks for the help.