Howto use more than one "Duet-Device"

Hallo,

I'm writing a Duet module for a MMS-5 (Mirage media player). This player supports up to 5 zones, where every zone needs a separate network connection. While this is not a problem, I want to have up to 5 "Duet-Device" to send and receive messages separate for each zone.

To initialize this I've written the following code:

DPS dps1 = new DPS(props.getProperty("Duet-Device"));
DPS dps2 = new DPS(dps1.getDevice(), dps1.getPort()+1, dps1.getSystem());
DPS dps3 = new DPS(dps1.getDevice(), dps1.getPort()+2, dps1.getSystem());
DPS dps4 = new DPS(dps1.getDevice(), dps1.getPort()+3, dps1.getSystem());
DPS dps5 = new DPS(dps1.getDevice(), dps1.getPort()+4, dps1.getSystem());
// Assign the virtual Duet device
vdvMedia1 = new NetLinxDevice(dps1, true);
vdvMedia2 = new NetLinxDevice(dps2, true);
vdvMedia3 = new NetLinxDevice(dps3, true);
vdvMedia4 = new NetLinxDevice(dps4, true);
vdvMedia5 = new NetLinxDevice(dps5, true);

And in the functions:

protected void doAddNetLinxDeviceListeners()
{
	vdvMedia1.addDataListener(this);
	vdvMedia2.addDataListener(this);
	vdvMedia3.addDataListener(this);
	vdvMedia4.addDataListener(this);
	vdvMedia5.addDataListener(this);
}

protected boolean doNetLinxDeviceInitialization()
{
	vdvMedia1.initialize();
	vdvMedia1.notifyOnline();
	vdvMedia2.initialize();
	vdvMedia2.notifyOnline();
	vdvMedia3.initialize();
	vdvMedia3.notifyOnline();
	vdvMedia4.initialize();
	vdvMedia4.notifyOnline();
	vdvMedia5.initialize();
	vdvMedia5.notifyOnline();
}

This works in the way that I can send out from the Duet-module any messages to the UI-module written in NetLinx. But messages from the UI-module to the Duet-module don't arrive, except for the first device (vdvMedia1).

What must I do to get the messages also from vdvMedia2 to vdvMedia5?

--
A.T.