We've got a production and development vcenter area that are both on the same subnet. No problems there. We then installed a dev and prod version of UpdateManager. Uh oh. When I go into VIC -> plugins, which one is showing? There's no way to know until you get the ssl cert warning. How do I change or get rid of the connection? By uninstalling VIC, dumping files and reinstalling. From there, make sure the VUM that you don't want isn't turned on. Yuck.
Did you know that the update signatures command is triggered on VirtualCenter not UpdateManager?