How can I allow Win XP users in LAN or Internet to use a passwd protected folder on MBWE as network storage for backup? It should be possible that more than one user is accessing the MBWE at the same time. Experimenting with adding users and protection settings didn't give me what I want. Any suggestions?
Lots of ways you can do this but here's your best bet:
Use the built-in Web management interface to first create your new user(s), then create new shares for the purpose of these users. Once they're created, disallow access for everyone BUT the user that needs into it.