[xwiki-users] preventing registration for unregistered users

Hi all, Working with 1.2-rc-1.6216 I'm failing to remove the default Register right for Unregistered Users by using the new Rights Management UI. Please, how could I edit the involved object without using the UI? It seems that the new RC2 is closer, but I would need to remove this option from a new virtual xwiki ASAP. Thanks for your help, Ricardo -- Ricardo Rodríguez Your XEN ICT Team