Websphere, Spring, Hibernate, JAX-WS Global Transactions - spring

Question

I am attempting to write a demo of a JAX-WS service participating in a global transaction. This is a model my organization will be doing more of as time goes on and we need to figure it out, but I am struggling.
I have a WSDL service being invoked from a client (which is also in a Java EE servlet with the same config...in fact it is the same server, but I can see that it is calling out over the wire to itself). Both are updating their rows, and then I throw an exception but the service will not rollback.
I have annotated a method that invokes both a local DAO update and the WSDL service client with #Transactional(propagation=Propagation.REQUIRED). That service in turn invokes another method, also anotated in the same way, which in turn calls a dao method to do another db update.
app-config.xml:
<jee:jndi-lookup id="wsdlDataSource" jndi-name="${es.ds.jndi}" />
<bean id="wsdlSessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="wsdlDataSource" />
<property name="packagesToScan" value="com.wsdl" />
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.DB2Dialect</prop>
<prop key="hibernate.connection.driver_class">com.ibm.db2.jcc.DB2Driver</prop>
<prop key="hibernate.bytecode.provider">javassist</prop>
<prop key="hibernate.show_sql">false</prop>
<prop key="hibernate.cache.use_second_level_cache">false</prop>
<prop key="hibernate.default_schema">k702prdr</prop>
<prop key="hibernate.transaction.factory_class">org.hibernate.transaction.JTATransactionFactory</prop>
<prop key="hibernate.transaction.manager_lookup_class">org.hibernate.transaction.WebSphereExtendedJTATransactionLookup</prop>
<prop key="jta.UserTransaction">java:comp/UserTransaction</prop>
</props>
</property>
<property name="annotatedClasses">
<list>
<value>com.wsdl.db.DBTrans</value>
<value>com.wsdl.db.UsrTrans</value>
</list>
</property>
</bean>
<!-- END Data sources -->
<!-- BEGIN Hibernate config and dependencies -->
<bean id="transactionManager"
class="org.springframework.transaction.jta.WebSphereUowTransactionManager" >
</bean>
<tx:annotation-driven transaction-manager="transactionManager"
proxy-target-class="true" />
I have followed some tutorials that had me go in to the Services view and add the WSTRansaction policy sets and bindings o the client and service (both generated initially from the RAD wizard), and then again into Admin Console applications->application Types->Websphere enterprise apps->my app->Service provider/client policy sets and bindings. There I added WSTransaction to client and service respectively at the parent application level (the policy inherits down to the endpoint).
But at the end of the day, no rollback is happening. Help! What am I missing? What have I misconfigured?
(update) - I found how to turn on the websphere transaction trace log in the admin console. It says (edited for brevity):
No transaction context found
Exit
Entry parm0=Operation: isAlive
No transaction context from incoming request
getTransactionManager parm0=com.ibm.ws.tx.jta.TranManagerSet#306e306e
These messages come with a bunch of what appear to be inspections of objects, and they repeat many times. Okay, so I appear to not be sending a transaction context from my client. But I still don't understand why. Anyone?
(update 2) - I discovered that my WSTRansaction policy sets for the service and client was not set to share, so i set it to share via the wsdl, and the trace log now seems to indicate that it is finding the transaction context...or at least, it's no longer explicitly saying it can't as above. It is saying some things like the following that may or may not means what i think they mean (again, edited for brevity if there is something meaningful you are not seeing, tell me, there is alot more info in there):
Entry parm0=XATransactionWrapper# 5f175f17 XAResource: com.ibm.ws.rsadapter.spi.WSRdbXaResourceImpl#5b7d5b7d enlisted: falseHas Tran Rolled Back = false mcWrapper.hashCode()490085686 parm1=XARESOURCE_NOTASSOCIATED
xa_start with flag: 0=TMNOFLAGS
setResourceStatus parm0=from NONE to REGISTERED
[at this point I see a log stmt that indicates my first update in the service]
setResourceStatus parm0=from REGISTERED to COMPLETING_ONE_PHASE
**setResourceStatus parm0=from COMPLETING_ONE_PHASE to COMMITTED**
setResourceStatus parm0=from NONE to REGISTERED
[at this point I see a log stmt that indicates my second update, which is done in the client]
setResourceStatus parm0=from REGISTERED to COMPLETING
setResourceStatus parm0=from COMPLETING to ROLLEDBACK
[at this point I see the stack trace of the hardcoded exception I am throwing]
So it seems pretty clear that while the transaction manager now sees both the client and service transaction, it thought it was supposed to complete the transaction on the service side as soon as that part was done, not realizing it was supposed to continue. Somehow I triggered a premature commit I guess. Ideas?