Hi orinoco,
you are bitten by a big change, they are migrating all translations into the packages themselves.
If that migration is done, there will be no kde-l10n-<LANG> left.
The best you can do is to write a bug against kwrite and kde-l10n-<LANG>.
Maybe they migrate, if enough people write a bug against kde-l10n-<LANG>, the working and right version from experimental to unstable,
or fix kwrite in the right way.
So please write a bug!