Microsoft Exchange 2013 iApp - Can't login to OWA or ECP if more than one server is active in pool

I am also almost done, but one more thing you could try is to set up a "pass through" performance L4 virtual server on port 443 at a different IP address, with a default pool containing your CAS servers, and SNAT Automap enabled, with no other profiles added to the VIP. The pool can be set for round robin load balancing. Point your clients at that VIP using the host file and see if it works; it'll still load balance between servers but none of our other optimizations will be used.