How to get Sage 5.4 working under the VM VirtualBox?

edit

I installed the Sage virtual machine 5.4 today. After booting things look as described here http://wiki.sagemath.org/SageAppliance at 3.3. I can use Sage directly from there.

However, I want to use http://localhost:8000. This works, but this time I see a window like the one here: http://www.sagenb.org/ and I do not succeed to log in. What is the username and the password?

(With Sage 5.0 I did not have this problem, things looked the same either way.)