Custom TaskLifecycleEventListener not picked up by TaskService if configured through Spring framework

Issue

• User developed a custom implementation of TaskLifeCycleEventListener class which implements the TaskLifeCycleEventListener interface like the following.

public class SimpleTaskLifeCycleEventListener implements TaskLifeCycleEventListener {

    @Override
    public void afterTaskStartedEvent(TaskEvent event) {}

    @Override
    public void afterTaskActivatedEvent(TaskEvent event) {}
...
}

And configured it as a Spring bean like this way.

...
    <bean id="taskService" class="org.kie.spring.factorybeans.TaskServiceFactoryBean" destroy-method="close">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
        <property name="transactionManager" ref="transactionManager" />
        <property name="userGroupCallback" ref="userGroupCallback" />
        <property name="listeners">
            <list>
                <ref bean="simpleTaskLifeCycleEventListener"></ref> 
            </list>
        </property>
    </bean>
    <bean id="simpleTaskLifeCycleEventListener" class="com.sample.task.listener.SimpleTaskLifeCycleEventListener">
    </bean> 
<bean id="runtimeEnvironment"
        class="org.kie.spring.factorybeans.RuntimeEnvironmentFactoryBean">
        <property name="type" value="DEFAULT" />
        <property name="entityManagerFactory" ref="entityManagerFactory" />
        <property name="transactionManager" ref="transactionManager" />
        <property name="assets">
                    ...
        </property>
        <property name="taskService" ref="taskService"/>
    </bean>
...

Unfortunately, this custom listener is never picked up by the TaskService. Is there a sample Spring based application which can demonstrate how to work with TaskLifecycleEventListener implementations in jBPM6 ?