When did I try to logon? After the restore had completed and the server was restarted. Is that what you meant to ask?
When you say I must logon as local admin to complete the Windows Setup phase i need to use local admin, what local admin? This is a Domain controller (SBS), there is no local admin account or local accounts whatsoever. I don't follow.
After restoring to the target server it prompts me to login as '.\Administrator' but we have never used a local admin account.
What do you mean by completing the Windows Setup phase? Do you mean when BESR is being installed on the source server, or after the restore is performed on the destination server?