Domain Mapping on a Wordpress multi-site

Hi,

I just made a single purchase of the Domain Mapping plugin for my Wordpress multi-site - but it is not installing properly.

After following the install instructions - my Network Admin does not show a Plugin's area.

I do have a Plugin's tab along the left of my super admin - it shows the sunrise file as a 'drop in' plugin and describes it as 'Executed before multi-site is loaded'.

How do I set this plugin up properly? Is this the correct plugin to be using for a multi-site and if it is not, how can I change it to get the correct plugin?

Thanks