RTC Java/Plugin API - How to set a project Area for Work Item?

What's the API method call to set Project Area for the given work item? Basically I am trying to move a Work Item from Project Area 'A' to Project Area 'B'.

I have a IWorkItem from WorkItemWorkingCopy, but I do not see any set method(s) to set Project Area. Someone mentioned that setContextId should work, but I don't think it works.

Below is the code snippet. The Save Status is 'OK'.

try
{
wiWorkingCopyMgr.connect(workItem, IWorkItem.FULL_PROFILE, monitor);
wiWorkingCopy = wiWorkingCopyMgr.getWorkingCopy(workItem);
copiedWorkItem = wiWorkingCopy.getWorkItem();
copiedWorkItem.setContextId(targetProjectArea.getItemId());
wiWorkingCopy.save(monitor);
}
catch (TeamRepositoryException e)
{
   // Log it
}