I tryed this, and all works good: Menu, Help file, and "Thesaurus" also are translated.
1) Download your language pack paying attention to select right version: http://mirror.switch.ch/ftp/mirror/OpenOffice/extended/
(Untill now (Sept. 24, 2007) you should download 2.2.1rc2 version in order to be compatible with the current downloadable version of OpenOffice portable (2.2.1.): http://mirror.switch.ch/ftp/mirror/OpenOffice/extended/2.2.1rc2/
2) Doubleclik an start installation: at the path request, click on browse button and select openoffice folder in PortableApps\OpenOfficePortable\App\
Now you can start patching.