Integrating existing hibernate functionality into Grails

My coworker and I inherited a jar that contains a few domain classes and a spring context that creates a session factory for Hibernate. This is a redacted version of the context file's hibernate pieces:

<tx:annotation-driven transaction-manager="transactionManager" />

<bean id="dataSource" class="com.ours.OurDataSource">
    <constructor-arg value="dml-rdbms-data-source.properties" />
</bean>

<bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
    <property name="sessionFactory" ref="searchSessionFactory" />
</bean>

<!-- Hibernate SessionFactory -->
<bean id="searchSessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
    <property name="dataSource">
        <ref local="dataSource" />
    </property>
    <property name="annotatedClasses">
        <list>
            <value>a.b.c.DefGhe</value>
            <value>a.b.c.Xyz</value>
        </list>
    </property>
    <property name="hibernateProperties">
        <bean class="our.com.ManagedPropertiesFactory" factory-method="getProperties">
            <constructor-arg value="hibernate.properties" />
        </bean>
    </property>
</bean>

I changed the sessionFactory bean to be called searchSessionFactory in order to avoid a name collision with the built-in grails hibernate session factory. That doesn't seem to help. I still get this error when trying to save a Grails-generated domain class:

Unknown entity: x.y.z.DomClass; nested exception is org.hibernate.MappingException: Unknown entity: x.y.z.DomClass

Has anyone run into a situation where they had to integrate existing hibernate functionality like this into Grails?