this is RHQ-1516. can't do it today - because even if you uninventory it, if those resources still exist, they get re-discovered/imported the next time the plugin is asked to perform discovery.
If the service resource (e.g. vhosts) really don't exist, I think there is a trick to do this - in the GUI URL, append "?debug=true" and I think they shows the uninventory button (???). I remember that used to be there, I'm not sure if that trick still works.