问NHibernate YesNo on SQL-Server CE不存在来自DbType AnsiStringFixedLength的映射

EN

 <class name="Audit" table="eolaudit_llk">
<id name="ID" column="eolauditlk_ky">
  <generator class="identity"></generator>
</id>
<property name="Name" column="eolauditlk_nm" />
<property name="Description" column="eolauditlk_dn" />
<property name="Active" column="active_fg" type="YesNo" />
<property name="UpdateUser" column="update_user_id" />
<property name="UpdateDateTime" column="update_dm"/>

        public static ISessionFactory CrashAndBurnCompactSQLSessionFactory(string ConnectionString)
    {
        return Fluently.Configure()
            .Database(MsSqlCeConfiguration.Standard
                .ConnectionString(ConnectionString)
                .ShowSql()
                .UseOuterJoin()
                .QuerySubstitutions("true 1, false 0, yes 'Y', no 'N'")
                .Dialect("NHibernate.Dialect.MsSqlCeDialect")
                )
            .Mappings(m =>
            {
                m.HbmMappings
                  .AddFromAssemblyOf<Audit>();
            })
            .ExposeConfiguration(BuildSchema)
            .BuildSessionFactory();
    }

    failed: System.ArgumentException: No mapping exists from DbType AnsiStringFixedLength to a known SqlDbType. at System.Data.SqlServerCe.SqlCeType.FromDbType(DbType type)
 at System.Data.SqlServerCe.SqlCeParameter.set_DbType(DbType value)