Use Xml field in SqlServer with nhibernate

public class XmlFieldUserType<T> : IUserType where T : ICloneable
{
    #region Equals member

    bool IUserType.Equals(object x, object y)
    {
        return (x == y) || ((x != null) && x.Equals(y));
    }

    #endregion

    #region IUserType Members

    public object Assemble(object cached, object owner)
    {
        return cached;
    }

    public object DeepCopy(object value)
    {
        if (value == null) return null;

        return ((T)value).Clone();
    }

    public object Disassemble(object value)
    {
        return value;
    }

    public int GetHashCode(object x)
    {
        return x.GetHashCode();
    }

    public bool IsMutable
    {
        get { return true; }
    }

    public object NullSafeGet(System.Data.IDataReader rs, string[] names, object owner)
    {
        Int32 index = rs.GetOrdinal(names[0]);
        if (rs.IsDBNull(index))
        {
            return null;
        }

        return XmlHelper.FromXml<T>((String)rs[index]);
    }

    public void NullSafeSet(System.Data.IDbCommand cmd, object value, int index)
    {
        if (value == null || value == DBNull.Value)
        {
            NHibernateUtil.String.NullSafeSet(cmd, null, index);
        }
        else
        {

            NHibernateUtil.String.Set(cmd, XmlHelper.ToXml(value), index);
        }

    }

    public object Replace(object original, object target, object owner)
    {
        return original;
    }

    public Type ReturnedType
    {
        get { return typeof(Uri); }
    }

    public NHibernate.SqlTypes.SqlType[] SqlTypes
    {
        get { return new SqlType[] { NHibernateUtil.String.SqlType }; }
    }

    #endregion
}

<property name="DetailData"
          type="NHibernateExt.XmlFieldUserType`1[[MyProject.DetailData, MyProject]], NHibernateExt"
           column="link_detail" />

INSERT INTO MyTable (link_url, link_sha256, link_target_id, link_details) VALUES (@p0, @p1, @p2, @p3); select SCOPE_IDENTITY(); @p0 = 'http://www.nablasoft.com', @p1 = 'BD827105DDFBEE299C04B461A322FFC21A1CC919D2FDB5A3E1CCC78B3D3BF93F', @p2 = '0', @p3 = '<DetailData
  UserName="Alkampfer"
  Title="Nablasoft HomePAge"
  Description="Not avaliable"
  Category="MySite">
  <Tags>one</Tags>
  <Tags>two</Tags>
  <Tags>three</Tags>
</DetailData>'