Download it here: http://www.heise.de/ct/projekte/offlineupdate/download_uk.shtml
GOTCHANote 1: CTUpdate cannot be run from a non-mapped drive, so make sure you map your repository first. The bat-file below expects %WPKG_DRIVE% to be set to this drive. Alternatively, you can modify the bat-file to temporarily map the drive. Note 2: Making proper reboot cycles etc. have not been paid attention to. CTUpdate does have functionality for resuming on reboot that is not enabled in the below setup.
Then run it in order to create a repository containing the languages and systems you want, but you do NOT need to create ISO files. The repository will be placed in the client subfolder. Then copy the entire tree over to the WPKG software folder and use the following entries: