InstaUp2Date – OS language

Hi! InstaNoob here, so prepare for the noobish questions. :) I have been testing out InstaUp2Date with CreateUser, FirstBoot and different installer packages + installerchoices and different catalogs and everything has worked out fine, more or less. Respect for Insta-developers! But when it comes to changing OS language it's isn't so swell anymore. Build scenario: Base OS / Installer disc OS X updates (Office 2011 + updates) (CreateUser) (FirstBoot) -> Restore -> Setup Assistant All the updates build like a charm, but when I restore the image I cannot define the OS language. Even if I manually change the language via Sys Pref > Language & Text and log out. So how can I define the OS language during the setup and get it work? At least Finnish and Swedish are needed in addition to English. Keyboard layout's are working fine. Also there must be a way for changing language later like with the basic OS X installation from install DVD. I have looked through thomasb's localization package and posts on this issue but it's too tedious at this point to manage or understand. I have also searched this forum on this issue but I haven't been able to find an answer. Best regards Omena