IList cats = session.CreateCriteria(typeof(Cat))
    .CreateCriteria("kittens")
        .Add( Expression.like("name", "Iz%") )
        .List();

Item
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0">
   <class name="Data.Dto.ItemDto,Data.Dto" table="ITEM" lazy="false">
      <id name="ItemId" column="ITEM_ID" type="Int32" access="field.lowercase" unsaved-value="0">
         <generator class="native"/>
      </id>
      <many-to-one column="BUID" name="Bu" class="Data.Dto.BusinessUnitDto,Data.Dto" access="field.lowercase" />
      <many-to-one column="ITEM_TYPE_ID" name="ItemType" class="Data.Dto.ItemTypeDto,Data.Dto" access="field.lowercase" />
      <property column="ITEM_NAME" type="String" access="field.lowercase" name="ItemName" not-null="true" length="50" />
      <property column="INTERNAL_KEY" type="String" access="field.lowercase" name="InternalKey" length="25" />
      <property column="ITEM_DESCRIPTION" type="String" access="field.lowercase" name="ItemDescription" length="100" />
      <many-to-one column="MANUFACTURER_ID" name="Manufacturer" class="Data.Dto.ManufacturerDto,Data.Dto" access="field.lowercase" />
      <property column="HEIGHT" type="Decimal" access="field.lowercase" name="Height" not-null="true" />
   </class>
</hibernate-mapping>

"Relationship-table" (btw what is the right term for such a table in English?) between property value and item to resolve the m:n relationship
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0">
   <class name="Data.Dto.ItemPropertyRelationDto,Data.Dto" table="ITEM_PROPERTY_RELATION" lazy="true">
      <id name="ItemPropertyRelationId" column="ITEM_PROPERTY_RELATION_ID" type="Int32" access="field.lowercase" unsaved-value="0">
         <generator class="native"/>
      </id>
      <many-to-one column="PROPERTY_VALUE_ID" name="PropertyValue" class="Data.Dto.PropertyValueDto,Data.Dto" access="field.lowercase" />
      <many-to-one column="ITEM_ID" name="Item" class="Data.Dto.ItemDto,Data.Dto" access="field.lowercase" />
      <property column="IS_ACTIVE" type="Boolean" access="field.lowercase" name="IsActive" not-null="true" />
   </class>
</hibernate-mapping>

Property value
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0">
   <class name="Data.Dto.PropertyValueDto,Data.Dto" table="PROPERTY_VALUE" lazy="true">
      <id name="PropertyValueId" column="PROPERTY_VALUE_ID" type="Int32" access="field.lowercase" unsaved-value="0">
         <generator class="native"/>
      </id>
      <many-to-one column="PROPERTY_ID" name="Property" class="Data.Dto.PropertyDto,Data.Dto" access="field.lowercase" />
      <property column="PROPERTY_VALUE" type="String" access="field.lowercase" name="PropertyValue" not-null="true" length="50" />
      <property column="IS_ACTIVE" type="Boolean" access="field.lowercase" name="IsActive" not-null="true" />
   </class>
</hibernate-mapping>

Manufacturer
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0">
   <class name="Data.Dto.ManufacturerDto,Data.Dto" table="MANUFACTURER" lazy="true">
      <id name="ManufacturerId" column="MANUFACTURER_ID" type="Int32" access="field.lowercase" unsaved-value="0">
         <generator class="native"/>
      </id>
      <many-to-one column="BUID" name="Bu" class="Data.Dto.BusinessUnitDto,Data.Dto" access="field.lowercase" />
      <property column="MANUFACTURER_NAME" type="String" access="field.lowercase" name="ManufacturerName" not-null="true" length="50" />
      <property column="ILN" type="String" access="field.lowercase" name="Iln" length="25" />
      <property column="INTERNAL_KEY" type="String" access="field.lowercase" name="InternalKey" length="25" />
      <many-to-one column="COUNTRY_ID" name="Country" class="Data.Dto.CountryDto,Data.Dto" access="field.lowercase" />
   </class>
</hibernate-mapping>