Unfortunately Hurricane Electric (or tunnelbroker.net) uses 6in4 tunnels. In order to create a tunnel, my first obstacle is an IP address that answers pings. As I am captured behind a badly configured CGN of a German cable provider (Telecolumbus), I am afraid it is not possible to use the service of HE.
So for the rest of the experiment I will stick to the infrastructure provided by SixXS (of course I am pretty sure that the service of HE would be excellent as well).