I looked up this page: http://b2evolution.net/man/contributing/translations/localization_howto?cat=92
That page speaks about version 0.9. I used the current stabled release - version 4.1.6.
I especially am confused by step 7. point a). and b). Is there a more accurate description somewhere? My PHP skills are not much, but that seems outdated to me.
Sorry we still have a lot of updating to do in the Manual.
The locales can now be created in the Settings > Locale Settings section of the back office.