cyrillic case converting with ru_RU.utf8 locale

all internal strings in my scripts and database are utf-8 encoded i want to convert case of cyrillic characters in the utf-8 string i'm setting setlocale (LC_ALL, 'ru_RU.utf8') using for example ucfirst () and got no any conversion, case of characters remains the same. latin characters are succesfully converting. locale ru_RU.uft8 exist on my system. did i miss smth? did i get smth wrong? Agri PS: i suppose that it is a problem of libc... but i hope... that smbd had solved the problem here....