Scopes, roles and permissions

Hi all,
Another question on Scopes.  We are defining Roles and Users.  We create a Role in the Global scope, we add the required permissions, we add a user and then we add the user to Member Role in a child scope.  The problem is that the user can't perform the actions in the child scope because he "doesn't have the required permission", but it should have them, because it should inherit permissions from the role in the global scope.
Please advice. Many thanks,
Ezequiel.