How to backup limited accounts profiles


I would like to know how can I, from and administrator account, set-up a backup of two limited accounts profiles. I can’t access the files, because they are private. I would rather not mess around with security settings of Windows XP as previous experiences proved disastrous…

Meanwhile, as Comodo Backup runs as service I thought that would do the trick. Right?

I want to set it up to run once a week, and so, even if someone log in with a limited account the job gets done.