As you suggested, I opened a new support incident - Microsoft Support Incident: SRX1062398920. This support incident has been ongoing for the past two weeks. The original issue remains - WOC hub does not display other Vista PCs in the circle. I am instructed in this incident to try the same things as the original support incident, which I faithfully do to make sure nothing is overlooked.
Finally I tried my own experiment, I installed and registered WOC on my ID on my work laptop while connected on my home network (the three Vista machines are on same home network). Within a short time the laptop shows up on my Vista hub PCs circle. When I removed WOC from the laptop the circle went back to no PCs in my circle.
The latest insult from the WOC tech support team, I was asked to uninstall Vista SP1 from all three PCs even though I had just installed it two weeks earlier and this issue started months ago.
I have stated that my support incident is non-trival and needs to get escalated. They just seem to ignore me and throw out other solutions that have already been tried. How do I get my issue escalated? Is there a support phone number?