kturtle handbook localization fails

Binary package hint: kdeedu

Starting "Kturtle Handbook" from kturtle on a "non-english" ubuntu variant (tested with ubuntu, xubuntu and kubuntu) displays the handbook in english, even if there is a localized version available.

to reproduce:
install a fresh copy of (*)ubuntu 10.04 and choose German at the install menu.
Install kturtle (and khelpcenter4 for not kde-based systems).
Start kturtle, choose help -> handbook. It is in English whereas I would expect it to be in German, as there is a
german version available online.

It doesn't help either to eliminate english as fallback language in kturtle & helpcenter.
Language commands in kturtle are correctly translated and can be used in English and German.

This is a long standing issue, it has persisted for at least 2 years.