I have a WP Multi User setup.
I have a sub site rubins.zenblogs.dk for a friend.
This friends own domain name, rubins.dk, should open up the rubins.zenblogs.dk sub site.
I have setup a A record for the rubins.dk DNS which points to the web server, which is a hosted web server.
I have also installed the Domain Mapping plugin so that rubins.zenblogs.dk will be redirected to http://www.rubins.dk.
But going to rubins.zenblogs.dk or http://www.rubins.dk just goes to the hosting providers generic webpage.