Synopsis: "include virtual cannot include remote documents State-Changed-From-To: open-closed State-Changed-By: marc State-Changed-When: Wed Nov 5 07:47:51 PST 1997 State-Changed-Why: mod_include never has allowed for the inclusion of remote documents, and likely never will. It is very difficult to implement well.
What you can do is use the proxy and a ProxyPass directive, eg.:
ProxyPass /foobar http://www.remote-site/
and then use "include virtual=/foobar/file.html".
