Controlling a computer abroad by teamviewer - Is there a roaming problem?

[runtis]

Dear all,
I would like to access my home computer (located in Austria) from work in Germany using teamviewer.
The computer in austria is connected to the internet via surfstick and is indicated as "online" when I start teamviewer. When I try to access the computer, teamviewer fails to establish a connection (first it says "connecting" for some time, then it goes back to "ready for connection").
While both computers where in Germany, there was no problem. So, do I have to change the settings in order to connect to the computer aborad?

I really hope that someone has an idea