I have had to implement an actionHandler that replaces the action because I want to be able to dynamically update the dueDate (see
http://www.jboss.org/index.html?module=bb&op=viewtopic&t=85157
and
http://www.jboss.org/index.html?module=bb&op=viewtopic&t=82969
)
So I have done the following in an actionHandler:

jbpmContext = executionContext.getJbpmContext();
 jbpmContext.save(executionContext.getProcessInstance());
 CreateTimerAction cta = new CreateTimerAction();

 //Timer and duedate are required fields
 cta.setTimerName(timerName);
 cta.setDueDate(strDueDate);

 if (transitionName != null)
 cta.setTransitionName(transitionName);
 if (repeat != null)
 cta.setRepeat(repeat);
 if (timerAction != null)
 //cta.setTimerAction((Action) Class.forName(timerAction).newInstance());
 cta.setTimerAction(new Action(new Delegation(timerAction)));

And done the following in a process:

<action class="com.homeq.payoffdemand.jbpm.actions.CreatePDWTimerActionHandler">
 <timerName>UPES_Wait_for_Expiry</timerName>
 <dueDate>fidelityMaintWait</dueDate>
 <transitionName>UPES_Wait_for_Expiry_Decision</transitionName>
 <timerAction>com.homeq.payoffdemand.jbpm.actions.upes.CalcWaitForExpiryActionHandler</timerAction>
 </action>

Does this seem reasonable? is there a better way? In PaRticular, how do I set the action. The above timerAction is an implementation of actionHandler, and I don't know if this is the correct way to set it into the setTimerAction call - see above.