To be honest, I haven't tested the help files much in non-english environments. I guess it's too much to ask Maemo to fall back to the en_GB help file if the fr_FR help file is not found. I guess I have to copy the english help file to new directories, one for each locale? What a disaster.... Maybe I'm missing something and there's a way to specify a "default" help file?
The only thing it "converts" is the repository info itself. All it really does is append ".db" to your former cache directory's name, after which it creates a new file and starts using that as the cache database. Yes, you need to re-download all your maps, but your old maps are still there, in case you ever want to go back to v1.x.