Short update: I get more and more used to the Prē - it's funny how you get used to mechanisms that are quite different to those you've been used to before.
Then I managed to connect to my University's Cisco VPN network - by simply installing "vpnc" pre packaged for nslu2. The only thing you should watch carefully is your "/etc/resolv.conf".
Only issue so far is the "not that well working" (ding-dong) touchstone charger and the battery life - but as I am a heavy homebrew user, the latter is probably my fault.