[O] Language format of clock/date entries

[Rainer Stengele]

Hi,

I have to switch languages in my wiodows 7 system from time to time.
After switching my clock entries also switch format.
How can I force emacs/orgmode to stick with the german clock/Date format like 
for example:
[2013-12-02 Mo]
[2013-12-03 Di]
[2013-12-04 Mi]
[2013-12-05 Do]
[2013-12-06 Fr]
..

Thanks,
Rainer