There is no lang*.ini file for the notification messages, as these are entered as plug-in options in the plug-in administration. I don't know which country you're from, but I have just tested entering Greek characters into the plug-in admin text field for notification part I and it worked all right (even with the Greek language files for the website not installed), in other words: I saw the Login One! notification message in Greek.
I don't know what is causing your problem. Please email me at webdesign(AT)innato.nl and we'll take it from there. I will probably ask you for temporary admin access to your website in order to investigate further.

hi,

as the title says, is there a way to override the notifications with translated messages for more than one language?
i can't find a lang*.ini file and the textfield in the plugin administration does not accept non-latin characters

thank you in advance