How do I change the language?

Hey,

how do I change the language (to German), so that charakters like "ö", "ä", "ü", etc are correctly displayed? Right now he's making out of "Christian Löffler" "Christian Lo~ffler" when I browse through tracks, which of course, doeesnt look good.

So,
-my Rekordbox Software is set to German
-on the XDJRX3 under "utilities" it's set to German
-when I plug in an USB and check the Player-settings in Rekordbox it sais "English".

First of all: why? When I set everything to German, why is it saying English? Shouldn't the USB "adapt" towards to setting of the player and software?
And second: under USB -> Player-Settings I cant seem to change the language. Is there a way to do it? Maybe that fixes it.