When you sign on, the application asks for both RL and SL identity. SL Bar Association in turns posts your RL identity, even though at Bar Assn meetings, it is the avatar that shows up and participates. It is not a big thing; however, it would seem that in-world, one would be dealing with the avatar and not the warm body on the other side of the keyboard. Obviously, when matters require RL interface the situation changes. As I say, not a complaint, just an observation.
I'm not sure exactly what you mean about logging in under your SL persona. If you make yourself an account under the persona's name, would that work for what you're looking for?
I didn't really set anything up here, the Ning system is already built, so I don't have much control over how it displays your info (other than the choices you can make on your own settings). Not sure if this addresses your concern or not.
Perhaps it's only me; however, it seems reasonable to keep a barrier between RL & SL. I am of the view that RL information about SL residents ought to be available to the public, including other members, only with the express consent of the resident. Obviously, certain information, such as credentials etc. may need to be made available to the SLBA for reasons of liability. On the other hand information such as RL names should be subject to at least some degree of protection. In other words, I would rather participate in the SLBA through the persona of my avatar than otherwise. I will participate however I must, but I could not find a way to log in simply using my avatar.