not sure if I have an older version but will check.
So I changed my wp-config.php to have DOMAIN_CURRENT_SITE as ec2-xx-xx-xx-xx.compute-1.amazonaws.com and now when I login to the network through the Amazon EC2 domain name it works and I can see all the sites and have all the network dashboard functions.
Under Sites it looks like the main site is also now ec2-xx-xx-xx-xx.compute-1.amazonaws.com (I assume this is due to the change in wp-config?)