Here's some code (stripped down) from my app which chains the XFRX listener along with some other listeners. See if it helps you get where you want to go.

*-- Create the XFRX Listener
This.oListener = XFRX('XFRX#LISTENER')

*-- Create a listenter for the progress bar
This.oListenerProgress = CREATEOBJECT('updatelistener')

*-- Chain the progress bar to XFRX listener
This.oListener.Successor = This.oListenerProgress

*-- If other listeners have been instantiated, chain them to the progress bar
IF VARTYPE(This.oListeners) = 'O' AND This.oListeners.Count > 0
	This.oListenerProgress.Successor = This.oListeners.Item[1]
ENDIF