I think this is a Flash security issue. Flash won't communicate with servers which do not have a correct crossdomain.xml file. This is so that server owners can restrict which Flash applications can communicate with the servers. And the RSS processing in Virtualization Manager is done on the UI, therefore I think that you have to put a crossdomain.xml file to your SharePoint's root. Try this tutorial and let me know how it goes. If you run into any trouble, there are plenty other tutorials out there, just search for something like 'SharePoint crossdomain.xml'
A good example of how the crossdomain.xml file looks is here
Hope this helps.
Excellent topic, not something I've heard or experienced before but after reading the info I see how it could apply. Not sure if they'll allow me to make this change, but i'll get back somehow with the results.
Thanks for the help.