Exchange 2010, I had Outlook 2013 pointing to my Exchange 2010 CAS Array VIP KEMP load balancer. Now that I'm on Ex2013, Outlook is using my Mailbox GUID as the server name. Now is Outlook not load balancing this on my

Where are you seeing this, in the properties of your mail profile in Outlook?  If so, that's correct; this is the new way in Exchange 2013.  What is the internal host name for Outlook Anywhere on your Exchange 2013 server(s) properties?  Ours is "outlook.our.domain", then in DNS we have "A" records with that same name and the IP of our two load balancers.  In Outlook, if I run the autodiscover connectivity test, it shows a successful connection to 'outlook.our.domain' which is answered by the load balancers and everything is working fine.

You're Outlook Profile will now use the mailbox GUID to connect to exchange.  It will still go through the load balancer, and will use the names on your HTTP Proxy settings in the Outlook Profile.

Is your question answered, or do you still need more assistance with this?