Are you talking about Test the AAA server or are you talking about an actual client authenticating?
If you are talking about a real client, there is not much you need to set on the ZD, just the IP address of the Radius server, the Shared Secret and the Auth port.
The rest, negotiation for security protocol to use is done between the Client and the radius server.
The ZD will just tunnel the authentication traffic between the client and Radius. If the client and Radius server are configured to use MSCHAPv2 it will work.
