I found another how-to this time specially for Strato and not 1&1:
I followed it and everything runs smoothly, now I have to clone my old system. What would be the easiest way? Shall I follow the http://www.howtoforge.com/howto_linux_systemimager
howto? Or do you suggest another way? I want to have a clone, then send an email to the site owners I host, to change their IP in the DNS where they manage their sites, so we can just hop onto the new server.
please keep in mind, that I want to synchronize a server running on interl to the enw one running on AMD and having setup software raid on the new one also I would like not to have to configure all applications like postfix, apache2 ispconfig again, except for the samll changes in hsotnames and IP - any chance to do that?