Puncake

Hi there, Been trying to change my control keys to how they are similar to Train simulator. I'm unable to bind decrease brake key to ' as it thinks that's push to talk which is bound to `. And also when i change a key, and try change it back, it still thinks its bound to that key so i can't re-change the key. I'm unsure if there's a way to manually change this via a file? Kind regards