Domain Mapping - Can't quite get my head round it

Ok so I've setup Domain Mapping plugin according to the instructions (as far as I can tell)...
Registered a domain & hosted it on my Hostgator reseller account (not the same name servers as my multisite which is on VPS)...
In the new domain hosting account have added an A Name record using the IP for my vps multisite (Hostgator told me the IP for allthingsquilting.com.au)...
And have added the domain name in Tools> Domain Mapping for the site the new domain is to be mapped to...
Have I missed something ?? Cause it's not working argghh!
Any help would be muchly appreciated.

cheers

Stef