So today I got my X1 finally.
Trying to add the PS4 gave me a little headache, since I wasn't able to find it in the devices. After some try and error, I found the option to connect a bluetooth device which worked without any problems. The Sofabaton was added as a keyboard, like my Harmony before.
Controlling works fine, but I would have expected some Playstation-specific key-names. It turns out, that in the App, standard keyboard-keynames are used and I have to figure out, that Backspace corresponds to Circle and Enter to X. Havent found out what square and Triangle are by now.
For a device, that is mentioned as supported in the Ads, I would have expected some more detail...