Translation, how to?

Hi,

I translated the language file "subscribe-by-email.pot" with POEDIT and saved it (as my language code is defined in the config.php) (FI.mo and FI.po) and transferred those files in to the languages-folder.

But nothing happens, all the texts are still in English.

As what name and how shall I make the translation to work?

Thanks in advance! This is really important to me and my site.