<property name="xmlDocument" column="xml_column" type="SqlServerXmlType"/>

public class SqlServerXmlType implements UserType, Serializable {
   private static final long serialVersionUID = -1626534232053785976L;
   @SuppressWarnings("unchecked")
   private static final Class RETURNED_CLASS = Document.class;
   private static final int[] SQL_TYPES = new int[] {java.sql.Types.LONGVARCHAR};
   

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#returnedClass()
    */
   @SuppressWarnings("unchecked")
   public Class returnedClass() {
      return RETURNED_CLASS;
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#sqlTypes()
    */
   public int[] sqlTypes() {
      return SQL_TYPES;
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#hashCode(java.lang.Object)
    */
   public int hashCode(Object aObject) throws HibernateException {
      return aObject.hashCode();
   }
   
   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#assemble(java.io.Serializable, java.lang.Object)
    */
   public Object assemble(Serializable aCached, Object aOwner)
         throws HibernateException {
      try {
            return SqlServerXmlType.stringToDom((String)aCached);
        }
        catch (Exception e) {
            throw new HibernateException("Could not assemble String to Document", e);
        } 
   }
   
   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#disassemble(java.lang.Object)
    */
   public Serializable disassemble(Object aObject) throws HibernateException {
        try {
            return SqlServerXmlType.domToString((Document)aObject);
        }
        catch (Exception e) {
            throw new HibernateException("Could not disassemble Document to Serializable", e);
        }
   }
   
   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#replace(java.lang.Object, java.lang.Object, java.lang.Object)
    */
    public Object replace(Object aOriginal, Object aTarget, Object aOwner) {
        return deepCopy(aOriginal);
    }
   
   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#equals(java.lang.Object, java.lang.Object)
    */
   public boolean equals(Object aObject1, Object aObject2) throws HibernateException {
      if(aObject1 == null && aObject2 == null) return true;
        else if (aObject1 == null && aObject2 != null ) return false;
        else return aObject1.equals(aObject2);
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#nullSafeGet(java.sql.ResultSet, java.lang.String[], java.lang.Object)
    */
   public Object nullSafeGet(ResultSet aResultSet, String[] names, Object aOwner)
         throws HibernateException, SQLException {
      if(names.length != 1)
         throw new HibernateException("names arrays has more than one element. can't handle this!");
      String xmlStr= (String)aResultSet.getObject(names[0]);
        try {
         return (xmlStr != null)?SqlServerXmlType.stringToDom(xmlStr):null;
      } catch (Exception e) {
         throw new HibernateException(e);
      }
   }

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#nullSafeSet(java.sql.PreparedStatement, java.lang.Object, int)
    */
   public void nullSafeSet(PreparedStatement aPreparedStm, Object aValue, int aIndex)
         throws HibernateException, SQLException {
      try {
         String xmlStr = null;
         if(aValue != null) {
            xmlStr = SqlServerXmlType.domToString((Document) aValue);
         }
         aPreparedStm.setObject(aIndex, xmlStr);
      } catch (Exception e) {
         throw new SQLException("Could not convert document to String for storage");
      }
   }
   
   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#deepCopy(java.lang.Object)
    */
   public Object deepCopy(Object aValue) throws HibernateException {
      if(aValue == null) {
         return null;
      }
      return ((Document)aValue).cloneNode(true);
   }
   

   /* (non-Javadoc)
    * @see org.hibernate.usertype.UserType#isMutable()
    */
   public boolean isMutable() {
      return false;
   }
   
    protected static String domToString(Document aDocument)  throws TransformerException
    {
       TransformerFactory tFactory = TransformerFactory.newInstance();
       Transformer transformer = tFactory.newTransformer();
       transformer.setOutputProperty(OutputKeys.INDENT, "yes");
       DOMSource source = new DOMSource(aDocument);
       StringWriter sw=new StringWriter();
       StreamResult result = new StreamResult(sw);
       transformer.transform(source, result);
       return sw.toString();
    }
   
    protected static Document stringToDom(String xmlSource)
         throws SAXException, ParserConfigurationException, IOException {
      DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
      DocumentBuilder builder = factory.newDocumentBuilder();
      return builder.parse(new ByteArrayInputStream(xmlSource.getBytes("UTF-8")));
   }