EF6 - TPH foreign key mapping in derived classes not working

gistfile1.cs

namespace ConsoleApplication1
{
    using System.Data.Entity;

    class Program
    {
        static void Main()
        {
            using (var db = new Context())
            {
                db.Database.Delete();
                db.Database.Initialize(false);
            }
        }
    }

    public class User
    {
        public int Id { get; set; }
    }

    public class Movie
    {
        public int Id { get; set; }
    }

    public abstract class Tag
    {
        public int Id { get; set; }
    }

    public class UserTag : Tag
    {
        public int UserId { get; set; }
        public virtual User User { get; set; }
    }

    public class MovieTag : Tag
    {
        public int MovieId { get; set; }
        public virtual Movie Movie { get; set; }
    }

    public class Context : DbContext
    {
        public DbSet<Tag> Tags { get; set; }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Tag>()
                .Map<UserTag>(m => m.Requires("TagType").HasValue("usertag"))
                .Map<MovieTag>(m => m.Requires("TagType").HasValue("movietag"));

            modelBuilder.Entity<UserTag>()
                .Property(m => m.UserId).HasColumnName("ItemId");
            modelBuilder.Entity<UserTag>()
                .HasRequired(m => m.User).WithMany().HasForeignKey(m => m.UserId);

            modelBuilder.Entity<MovieTag>()
                .Property(m => m.MovieId).HasColumnName("ItemId");
            modelBuilder.Entity<MovieTag>()
                .HasRequired(m => m.Movie).WithMany().HasForeignKey(m => m.MovieId);
        }
    }
}

so did you found any solution for this issue?