My home network is a little screwed up, because I have IPTV (Telus Optik) and I am using the RJ45 jacks in the back of my PVR and my Digital Tuner to plug in my WD Live hub and my WD Live plus. ( see http://bit.ly/gUNBrI )
Anyway, the result is that I can't have any UDP traffic between the WD devices, and other devices in my network connected via wifi.
The SSDP re-advertisement feature in plugplayer solves the problem for the media server in the WD Live hub, but I still can't autodiscover the media renderers in the two devices. It would be great if I could use SSDP Re-Advertisement on the renderers.