From the 1and1 FAQ'S
How do I login to edit my Blog?
The blog has a management interface which you can use to manage your blog site.
You can login one of two ways:
1. Click 1&1 Blog in the 1&1 Control Panel and then click launch.
2. To login go to the url:
Note: You will need to replace "www.domain.com" with your domain name the blog is located on.
This was specified by the user during blog creation.
So far I have downloaded the wordpress software and did an install of the software from scratch so I can fully mess with it.
I wonder if 1and1 does not allow you much freedom when you set up a blog from the administration panel.