Multilanguage User Interface for OOOport 3 missing

I would like to switch in OOOport from an English to a foreign language user interface (like Czech, Italian, German etc).

In the OPTIONS - LANGUAGE SETTINGS - LANGUAGES menu the language of user interface only shows English. In the help page one finds: "Select the language used for the user interface, for example menus, dialogs, help files. You must have installed at least one additional language pack or a multi-language version of OpenOffice.org."

I didn't manage to find the proper source of these user interface packages (not spelling etc, that works).

Anyone out there who knows the source?

Or is there a trick to copy the language part from one of the localized versions into my English portable OOO? I would not like to have several different OOO versions installed on my computer.