Is there a mechanism to do a silent login into a private store? We have an existing system that manages member information outside of BV and will create and manage users via the webservices included in BV. The member system will provide a unified usernanname/password between systems. This is easily accomplished using the web service methods to manage users and keep them in sync. Only a registered user in our member system can access the bv cart, how do we do a handoff to bv to prevent the user from having to login again to shop?