Need to restore a mailbox for a server and domain that no longer exist

Hi,

I have a client who needs a users mailbox restored from back in Jan 2010. Normally this wouldn't be a huge issue, however the server and domain that the backup was created on no longer exist. I try to restore from tape but just get an error "Unable to attach to a resource" which would make sense I guess as it would be trying to authenticate against the old domain controller.

Is there a way I can restore the mailbox in the new environment?

We use BE 12.5, the server was an SBS 2003 server with Exchange 2003. We currently run Exchange 2007 in our environment.

Thanks