gistfile1.xsl

<class name="NHibernate.Auction.Category, NHibernate.Auction">
    <id name="Id" column="ID"/>
    ...
    <bag name="Items" table="CATEGORY_ITEM" lazy="true">
        <key column="CATEGORY_ID"/>
        <many-to-many class="NHibernate.Auction.Item, NHibernate.Auction" column="ITEM_ID"/>
    </bag>
</class>

<class name="NHibernate.Auction.Item, NHibernate.Auction">
    <id name="id" column="ID"/>
    ...

    <!-- inverse end -->
    <bag name="categories" table="CATEGORY_ITEM" inverse="true" lazy="true">
        <key column="ITEM_ID"/>
        <many-to-many class="NHibernate.Auction.Category, NHibernate.Auction" column="CATEGORY_ID"/>
    </bag>
</class>