Version 1.99.16
Tried several times to translate singular/plural strings, but it is not saved in .po and therefore not converted in .mo
e.g. (copypaste from the plugin's screen) from a string in comments.php:
Singolare: One Response to %2$s
Plurale: %1$s Responses to %2$s
Risultato indice plurale = 0 Una Risposta a %2$s
Risultato indice plurale = 1 %1$s Risposte a %2$s
workaround: open the .po in an editor like vim, manually translate and save, open the .po with the plugin and generate .mo correctly.
http://wordpress.org/extend/plugins/codestyling-localization/