Mapeamento com hibernate

por favor me ajudem com este mapeamento to quebrando a cabeca com isso.
valew galera

clientes.hbm.xml

<?xml version="1.0"?>  
    <!DOCTYPE hibernate-mapping PUBLIC  
       "-//Hibernate/Hibernate Mapping DTD 3.0//EN"  
       "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">  
    <hibernate-mapping>  
        <class name="model.clientes" table="clientes">  
           <id name="id_cliente"></id>  
            <property name="nome"/>                   
              <set name="itens">
<key column="id_item"/>
<one-to-many class="model.itens"/>
</set>            
       </class>  
   </hibernate-mapping>  


contas_receber.hbm.xml
<?xml version="1.0"?>  
    <!DOCTYPE hibernate-mapping PUBLIC  
       "-//Hibernate/Hibernate Mapping DTD 3.0//EN"  
       "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">  
    <hibernate-mapping>  
        <class name="model.contas_receber" table="contas_receber">  
           <id name="id_conta_receber"></id>  
            <property name="data_pagamento" type="java.util.Date"/>  
            <property name="data_a_pagar" type="java.util.Date"/>  
           <property name="forma_pagamento"/>
           <property name="dados_pagamento"/>
           <property name="parcela"/>     
            <property name="valor"/>            
              <property name="venda"/>     
                <many-to-one name="venda"
                class="model.vendas"/>         
       </class>  
   </hibernate-mapping>


itens.hbm.xml
<?xml version="1.0"?>  
    <!DOCTYPE hibernate-mapping PUBLIC  
       "-//Hibernate/Hibernate Mapping DTD 3.0//EN"  
       "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">  
    <hibernate-mapping>  
        <class name="model.itens" table="itens">  
           <id name="id_item"></id>  
            <property name="clientes" />  
            <property name="produtos" />
           <property name="Vendas"/>              
               <many-to-one
                name="clientes"
                class="model.clientes" column="id_cliente"/>            
                                    <many-to-one
                                     name="produtos"
                                     class="model.produtos" column="id_produto"/>          
                                                             <many-to-one 
                                                              name="vendas"
                                                              class="model.vendas" column="id_venda"/>            
                 
       </class>  
   </hibernate-mapping>  



produtos.hbm.xml
<?xml version="1.0"?>  
    <!DOCTYPE hibernate-mapping PUBLIC  
       "-//Hibernate/Hibernate Mapping DTD 3.0//EN"  
       "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">  
    <hibernate-mapping>  
        <class name="model.produtos" table="produtos">  
           <id name="id_produto"></id>  
            <property name="descricao"/>  
            <property name="estoque"/>  
           <property name="estoque_minimo"/>  
           <property name="preco_custo"/>  
           <property name="preco_venda"/>  
           <property name="data_cadastro" type="java.util.Date"/>         
             <set name="itens">
             <key column="Itens"></key>
             <one-to-many class="model.itens"/>
</set>   
       </class>  
   </hibernate-mapping>
   
   
   
   
   
   vendas.hbm.xml
    <?xml version="1.0"?>  
    <!DOCTYPE hibernate-mapping PUBLIC  
       "-//Hibernate/Hibernate Mapping DTD 3.0//EN"  
       "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">  
    <hibernate-mapping>  
        <class name="model.vendas" table="vendas">  
           <id name="id_venda"></id>  
            <property name="data_venda"/>  
            <property name="desconto"/>  
           <property name="forma_pagamento"/>
           <property name="total"/>     
                   
           <set name="contas_receber">
          <key column="ContasReceber"/>
          <one-to-many class="model.contas_receber"/>
          </set>  
               
 <set name="itens">
<key column="Itens"/>
<one-to-many class="model.itens"/>
</set>  

 
       </class>  
   </hibernate-mapping>
   
   
   
     


olha o erro ai


4/11/2007 21:23:05 org.apache.catalina.core.StandardHost getDeployer
INFO: Create Host deployer for direct deployment ( non-jmx ) 
14/11/2007 21:23:05 org.apache.coyote.http11.Http11Protocol start
INFO: Starting Coyote HTTP/1.1 on http-8080
14/11/2007 21:23:05 org.apache.jk.common.ChannelSocket init
INFO: JK2: ajp13 listening on /0.0.0.0:8009
14/11/2007 21:23:05 org.apache.jk.server.JkMain start
INFO: Jk running ID=0 time=0/31  config=null
14/11/2007 21:23:05 org.apache.catalina.startup.Catalina start
INFO: Server startup in 4062 ms
14/11/2007 21:24:52 org.hibernate.cfg.Environment <clinit>
INFO: Hibernate 3.0.5
14/11/2007 21:24:52 org.hibernate.cfg.Environment <clinit>
INFO: hibernate.properties not found
14/11/2007 21:24:52 org.hibernate.cfg.Environment <clinit>
INFO: using CGLIB reflection optimizer
14/11/2007 21:24:52 org.hibernate.cfg.Environment <clinit>
INFO: using JDK 1.4 java.sql.Timestamp handling
14/11/2007 21:24:52 org.hibernate.cfg.Configuration configure
INFO: configuring from resource: /hibernate.cfg.xml
14/11/2007 21:24:52 org.hibernate.cfg.Configuration getConfigurationInputStream
INFO: Configuration resource: /hibernate.cfg.xml
14/11/2007 21:24:52 org.hibernate.cfg.Configuration addResource
INFO: Mapping resource: itens.hbm.xml
14/11/2007 21:24:52 org.hibernate.cfg.HbmBinder bindRootPersistentClassCommonValues
INFO: Mapping class: model.itens -> itens
14/11/2007 21:24:52 org.hibernate.cfg.Configuration addResource
INFO: Mapping resource: contas_receber.hbm.xml
14/11/2007 21:24:52 org.hibernate.cfg.HbmBinder bindRootPersistentClassCommonValues
INFO: Mapping class: model.contas_receber -> contas_receber
14/11/2007 21:24:52 org.hibernate.cfg.Configuration addResource
INFO: Mapping resource: clientes.hbm.xml
14/11/2007 21:24:52 org.hibernate.cfg.HbmBinder bindRootPersistentClassCommonValues
INFO: Mapping class: model.clientes -> clientes
14/11/2007 21:24:52 org.hibernate.cfg.Configuration addResource
INFO: Mapping resource: vendas.hbm.xml
14/11/2007 21:24:53 org.hibernate.cfg.HbmBinder bindRootPersistentClassCommonValues
INFO: Mapping class: model.vendas -> vendas
14/11/2007 21:24:53 org.hibernate.cfg.Configuration addResource
INFO: Mapping resource: produtos.hbm.xml
14/11/2007 21:24:53 org.hibernate.cfg.HbmBinder bindRootPersistentClassCommonValues
INFO: Mapping class: model.produtos -> produtos
14/11/2007 21:24:53 org.hibernate.cfg.Configuration doConfigure
INFO: Configured SessionFactory: null
14/11/2007 21:24:53 org.hibernate.cfg.Configuration secondPassCompile
INFO: processing extends queue
14/11/2007 21:24:53 org.hibernate.cfg.Configuration secondPassCompile
INFO: processing collection mappings
14/11/2007 21:24:53 org.hibernate.cfg.HbmBinder bindCollectionSecondPass
INFO: Mapping collection: model.clientes.itens -> itens
14/11/2007 21:24:53 org.hibernate.cfg.HbmBinder bindCollectionSecondPass
INFO: Mapping collection: model.vendas.contas_receber -> contas_receber
14/11/2007 21:24:53 org.hibernate.cfg.HbmBinder bindCollectionSecondPass
INFO: Mapping collection: model.vendas.itens -> itens
14/11/2007 21:24:53 org.hibernate.cfg.HbmBinder bindCollectionSecondPass
INFO: Mapping collection: model.produtos.itens -> itens
14/11/2007 21:24:53 org.hibernate.cfg.Configuration secondPassCompile
INFO: processing association property references
14/11/2007 21:24:53 org.hibernate.cfg.Configuration secondPassCompile
INFO: processing foreign key constraints
org.hibernate.MappingException: Could not determine type for: java.util.Set, for columns: [org.hibernate.mapping.Column(venda)]
	at org.hibernate.mapping.SimpleValue.getType(SimpleValue.java:265)
	at org.hibernate.mapping.SimpleValue.isValid(SimpleValue.java:252)
	at org.hibernate.mapping.Property.isValid(Property.java:174)
	at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:325)
	at org.hibernate.mapping.RootClass.validate(RootClass.java:188)
	at org.hibernate.cfg.Configuration.validate(Configuration.java:839)
	at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1000)
	at model.OpenSessao.<init>(OpenSessao.java:9)
	at control.clienteDao.insert(clienteDao.java:16)
	at org.apache.jsp.adicionaCliente_jsp._jspService(adicionaCliente_jsp.java:67)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)

Cara eu recomendo você começar a usar anotações você não acha mais façil?

ainda nao conheco tem algum tutorial aqui no guj?

Eu não lembro o link que usei quando tava aprendendo mas tem esse aqui:
http://hibernate.bluemars.net/152.html?cmd=prntdoc
em inglês.

anotatations eh muito mais facil mesmo!
tenta usar… acho que eh isos que tah dando problema no seu hibernate tbm…