Need more info for LoginAsync

using System;
using System.Security.Principal;
using IdeaBlade.EntityModel;
using System.Runtime.Serialization;
namespace SilverlightApplication2
{
#if !SILVERLIGHT
    public class SimpleLoginManager : IEntityLoginManager
    {
    #region IEntityLoginManager Members
        public IPrincipal Login(ILoginCredential credential, EntityManager entityManager)
        {
            return new UserBase(new GenericIdentity(credential.UserName), null);
        }
        public void Logout(IPrincipal principal, EntityManager entityManager)
        {
        }
        #endregion
    }
#endif
    [DataContract]
    public class GenericIdentity : IIdentity
    {
        #region IIdentity Members
        public GenericIdentity(string name)
        {
            Name = name;
            IsAuthenticated = true;
        }
        public string AuthenticationType
        {
            get;
            internal set;
        }
        public bool IsAuthenticated
        {
            get;
            internal set;
        }
        public string Name
        {
            get;
            internal set;
        }
        #endregion
    }
}