Now that I have spent the whole day to set up the experiment, a multisite in WordPress and then subsequently work with the multisite language switcher, finally i gave up.
Seems that my Provider One.com, doesn’t support Subdomain Handling in WordPress.
Now I#m trying out the qTranslate X Plugin, which is far easier to install and better manageable. I’ll continue to write on this topic when I am more experienced in handling the plugin.

Enjoy !