If you are putting the english locale in the right folder,it differs betwheen images.Think Kewelt has it in /var Tuxbox/config/locale.
It should work if the uploaded locale is the correct one for the image.After upload and restart go to the menu and select sprache.
Personaly as you can see im using GLJ wich I find moore emu freindly.Used to use keywelt though.
LinuxPC Debian gboxserver 2.25 I=2 X=5
1xRelook400 FantacyNuemo 2.13.6 gbox 2.25
Dbox2 Philips 2x1 GLJ image gbox 2.25
Dbox2 Sagem 1x1 GLJ image gbox 2.25
Delete D-line from gigabox boxid 3017