Command line option --language is broken

[rgerrits]

I have a idx/sub with several languages, idx 0 being Danish and idx 6 being Dutch.

To export the Dutch subtitles, I run:
java -jar BDSup2Sub512.jar --language nl -o output.idx input.idx

The result has the Danish subs, but according to the idx, they are english:
id: en, index: 0

I also tried this using the GUI:
This also results in Danish subs, but now at least the idx says the subs are Dutch.

(So the only way i can use it: first textedit .idx and set langidx to the desired subtitle, and then use the GUI to export. Thus not usable if needing to process lots of subs.)