1. Copy the MUI language pack sources into your office source folder (do not replace available items)
2. In the OMUI.XX-YY folder for the specific language customize the config.xml as listed below:
3. Install the Language with the following command, where the setup.exe is the original from the office 2007 source, not from the language pack.
\\server\office\setup.exe /config \\server\office\omui.xx-yy\config.xml