Changing domain; offline files?

Archived from groups: microsoft.public.win2000.setup_deployment (More info?)

I have a laptop which was part of my old domain and the user logged on in
cached mode and worked with a lot of files in "offline mode".
However, nobody told me about this setup. So when I moved the computer to
the new domain, his offline files are gone.
I have his old profile (from documents and settings) on backup, ,but I don't
find the files anywhere in that dit.
Is there any way to retreive those files even thought the user has a new
username and the computer now is in a new domain?
I still have access to the old domain, but the user account has been
deleted. Creating the username again and changing back to the old domain was
one suggestion I got. However, I fail to see the logic in that, since a new
username would mean a new Unique ID in the AD and thus that would mean a "new
user" for the client even if the username is the same?