appHost.Plugins.Add(new AuthFeature(() => new CustomUserSession(), new IAuthProvider[] { new CustomBasicAuthProvider() }) { IncludeAssignRoleServices = false });

public class CustomUserSession : AuthUserSession
        {
            public SecurityContext SecurityContext { get; set; }
        }

public class CustomBasicAuthProvider : BasicAuthProvider
{
    public override bool TryAuthenticate(IServiceBase authService, string userName, string password)
    {
        var session = (CustomUserSession)authService.GetSession();
        session.SecurityContext = new SecurityContext { Username = userName, Password = password };
        authService.SaveSession(session, SessionExpiry);
        return true;
    }
}

[Authenticate]
    public class PlayerService : Service
    {
        public IPlayerProvider PlayerProvider { get; set; }

        private CustomUserSession UserSession
        {
            get
            {
                return base.SessionAs<CustomUserSession>();
            }
        }

        public AddPlayerResponse Post(AddPlayerRequest request)
        {
            return PlayerProvider.AddPlayer(request, UserSession.SecurityContext);
        }
    }

container.RegisterAutoWired<PlayerService>();

container.RegisterAutoWired<PlayerService>().ReusedWithin(ReuseScope.Request);