realmlist change

Hello everybody!

First, sorry for my english.
I´m from a german server and want to start new here, because of the much populated realms.
So I downloadet the game for a second time from this website, because I thought that would be the most easy way to connect to yor servers.
But I want to have a look to my old server too, at least sometimes. Sadly it´s not possible to transfer the characters.
My question is, if it is somehow possible to connect to my old sever. If that is possibel, how can I do that?
At the moment I am able to change the realmlist, but the server doesn't changes. Why?

Thanks a lot for your help!

Palancar

/edit
I solved the promblem