Here is a workaround that worked for me:
VS will actually do remote debugging. It's just that it wants to check *locally* in the metabase (or equivalent in Vista/W28) first to be sure the site exists, which is a bug.
The workaround is to install IIS locally, then setup a local site with the same name as the remote site (just add a host header alias for the default local site). Use ping to be sure DNS is finding the remote site, not the local site.
Now the web section of the properties page will let you set the IIS option. From that point debugging works just fine!
I also posted this to Connect.
Mike Gilbert
Software Leverage, Inc.