Gettext translations are cached. If you change *.mo files your page may not be translated as expected. Here's simple workaround which does not require restarting webserver (I know, this is just a dirty hack):
<?php
function initialize_i18n($locale) {
putenv('LANG='.$locale);
setlocale(LC_ALL,"");
setlocale(LC_MESSAGES,$locale);
setlocale(LC_CTYPE,$locale);
$domains = glob($locales_root.'/'.$locale.'/LC_MESSAGES/messages-*.mo');
$current = basename($domains[0],'.mo');
$timestamp = preg_replace('{messages-}i','',$current);
bindtextdomain($current,$locales_root);
textdomain($current);
}
?>
to make this work you have to put your locale inside file messages-[unix_time].mo and use this name (without .mo) as your domain to fool caching mechanism (domain names differ)
msgfmt messages.po -o messages-`date +%s`.mo
for me this works fine (although this is not very elegant solution)