Alan
I do not believe that it is possible to modify the request to the same authentication server based on which interface the login attempt comes from. If you set it up so that authentication of console was one server and authentication for VTY was a different server, then I believe that you could get this to work. But if it is the same authentication server for both console and VTY then I do not believe that you can treat the same user differently based on which interface.
HTH
Rick
HTH
Rick