Thanks for the response, but I don't think your understanding the issue.
My USMT 4.0 is setup to migrate this information, and does so without much issue. On some machines, Outlook will not open unless I go to Control Panel -> Mail and re-enter the username, then click Check Name. Then it is detected without issue.
My Question is this, what is the registry key that holds this information?
If I had that I could modify it with a Script after the Restore of the users data.