Adding a language to my debranded W715

[ragalthar]

Hello, I debranded my W715 from Vodafone Germany (CDA 1221-7222) to nordic (CDA 1209-4769). Now I'd like to add the german language which doesn't belong to the nordic custpack. So I copied the language files to /tpa/preset/system/language with the A2Uploader. But still I cannot choose this language when being in Menu -> Settings -> Language -> Phone language. What do I have to do to be able to choose it there?

Please be aware that I'd still like to be able to update my phone via SEUS when a new FW is available.

[Edit] Also I'd like to remove the Vodafone hardware branding. Is it possible to remove it? How? Does SE send me a new label when I "lost" my old one?