exception is org.hibernate.MappingException: Could not determine type for: nl.digirap.model.registration.DurationType, at table: CYCLUS, for columns: [org.hibernate.mapping.Column(TYPE)]

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
   <class name="nl.digirap.model.registration.Cyclus" table="CYCLUS"
      lazy="false">
      <id name="id" column="ID" type="integer">
         <generator class="sequence">
            <param name="sequence">CYCLUS_SEQ</param>
         </generator>
      </id>
      <property name="description" column="DESCRIPTION" type="string" />
      <property name="duration" column="DURATION" type="float" />
      <property name="durationType" column="TYPE" type="nl.digirap.model.registration.DurationType" />
   </class>
</hibernate-mapping>

<many-to-one
   name="durationType"
   column="TYPE"
   class="nl.digirap.model.registration.DurationType"
/>