Sorry to be the bearer of bad news, but this remote does not work with your PB. It needs to be recogniced as a keyboard. There is a long thread about possible compatible remotes in the German forum you allready know. To summarize it: older bluetooth version are most probably working, ble devices don't. PB has promiced to support more devices in the future but I don't know a date.
Edit: Here is the thread:
https://www.e-reader-forum.de/t/welc...ienung.159820/