[Göran]

Thank you Kar-l and _ck_ for your answers.

CyrNickName might be useful but where can I find it? It is not in the list of plugins and it might be possible to download from a site a found in Russian but I do not understand russian so I could not use it. After more searching I found http://bbpress.ru/downloads/plugins/ where I could download it and it seems to work fine.