How do I get Multi-domains to work with stand-alone domains

I want to set up the multi-domains plugin to work with stand-alone domains e.g.

I have the plugin working with sub-domains with Wordpress Multisite setup to use sub-domains as specified in your usage documentation. "Multi-Domains is for sub domain installations only and will not work well for subdirectory installations."

When I try to setup a site after adding a new domain I still have to specify a name otherwise the form won't validate. So instead of getting I get I've tried to get around this by add www as name so that I get and as you've probably guessed this doesn't work. redirects to multi-site sign up page will give me an error 500

However will display the contents of the read me.