Yes I'm using the "WordPress MU Domain Mapping" plugin.
My Domain Mapping Configuration is a Server IP Address and the other settings are:
Checked: "Remote Login"
Unchecked: "Permanent redirect (better for your blogger's pagerank)"
Checked: "User domain mapping page"
Checked: "Redirect administration pages to site's original domain (remote login disabled if this redirect is disabled)"
Unchecked: "Disable primary domain check. Sites will not redirect to one domain name. May cause duplicate content issues."
(If that was the setting you where looking for.)