This is exactly my point: saved configuration got overwritten by one of startup scripts!

May be I should be installing in Debian mode not in Knoppix. But it is too late anyway (3 PC migrated).

One good news: in 3.9 this script changed in such way that 'tz' setting, when provided as kernel boot option,would overwrite the language default. But not for other ones (keyboard and etc).

So this posting is just for other people to know.