We had a similar issue with Apple TV and Iphone, but in our case IPhone
never discovered the Apple TV which was connected to the WAN port and
then found the issue was with Multicast forwarding need to be enabled
and we enabled the mulitcase policy an...
There should not be a problem in connecting IPAD' s or IPhone with
certificates, I have connected several IPADs to FortiAP' s even with
invalid(expired) certificates and it works fine. What is the Radius
server you are using ?