Teensy controller – manually write controller config file

Hi, I have made a custom gamepad/controller using an Arduino type called Teensy. For some reason The auto-controller-configuration in retropie does not save my configuration-file in the /opt/retropie/configs/all/retroarch-joypads directory. Therefore I would like, to write the file manually. How do I do this? Do I just edit one of the pre-configured controller files to the right name, button-numbers and hotkeys?
Thanks