We managed to hijack this post.
Which is not good.
Honestly, I never got that modem working with Linux. But it works with Mac Os X, weird.
I am using DSL-500G configured to work in bridged mode. Don't like the router function in the small box.
However, you may want to provide the following information:
1. Can you log into the modem's web management interface?
2. Are you using custom compiled kernel?
3. Is it possible to try to log on using other modem then the crappy Telekom's?
Since this post, I have learned a few things about pppoe in Linux.
1. You don't have to have the NIC configured with and IP OR set it to dhcp. Blank would do.
2. You can always go back to /etc/ppp/ and check the config files there.
3. You will get a ppp0 interface when you are connected.