Masteruser password help

Hi!

I set up an xbox for a grouphome a while back and one of the kids tried to 'hack' it (silly kid).

I had the good sense to set up a password for the master user and lock the kids out of sensitive stuff, so all he managed to do is delete all the users other than the master user.

The staff at the grouphome picked the password and I wrote it down for them on the info sheet I gave them and told them to write it down as well, but they have lost the pass and no one remembers it.

I can FTP to the box, but can't find the xml to reset or change the master user password.

Any help would be great!

system/profiles.xml