MDT 2013 and Autologon headache

I have been struggling for days trying to get Autologon to Work during MDT 2013 deployment. I have recreated task sequence, recreated custom WIM file, looked at unattended.xml hundred times but somehow after OS deployment, It reboots and tries to login with wrong username or wrong domain name. I want it to login as local Administrator on Local Machine but somehow it insists on using local Administrator and our Domain name as "Login From" and it fails. My Unattend XML file on the Task Sequence has following entries:

 <AutoLogon>
                <Enabled>true</Enabled>
                <Username>Administrator</Username>
                <Domain>.\</Domain>
                <Password>
                    <Value>xxxxx</Value>
                    <PlainText>false</PlainText>
                </Password>
                <LogonCount>999</LogonCount>
  </AutoLogon>

I have tried putting "." in Domain Name.

Can anyone tell me where in MDT does it set Autologon Registry? Does it come from Unattend.XML in Task Sequence, which script sets Autologon Registry?. I don't mind manually hardcoding Registry Entry for Autologon but do not know where in task sequence I would put it.

It only is a problem with this Task Sequence where I am using Custom Image. I have another task sequence where I use vanilla OS image with same autologon entry in unattended.xml and it works fine.

I am at a total loss.

Thanks,

Deepak