Okay, now I managed to get this file persistent in xorg.conf.d, but it won't be called for unknown reasons. Just by restarting the xserver it gets called, at boottime it is ignored.
(I am still not sure, what went wrong the first time, I tried to make it persistent. Might be a stupid coincidence of my own stupidity and some strange behaviour of TC. First time I checked the folder, the file wasn`t there, then I changed the scripts and did a backup, and again the file wasn`t there. No error message by the backup script... I then changed the scripts again and rebooted. Keyboard layout didn`t work, so I presumed, that the file wasn`t there again, but obviously it was, but not working for some reason... Well, I`m getting old...)