I got this working by setting up a fresh site and then copying the web.config on top of the existing one and making changes to the <wsFederation passiveRedirectEnabled="true" issuer="
so that it point correctly. Now the front end is working and the back end.
Now my problem is that I am unable to Publish or SaveAsDraft. I get The remote server returned an unexpected response 400 Bad Request.
Anyone have any ideas? I do like the ability of getting into the back end now without having to log in.