Hi Greg,
I found why it didn't work.
In my lab, End user was connected to UAG through HTTPS and UAG was connected to CAS server through HTTP
Configuration:
In CAS Server
"Require SSL" not checked on default web site
In UAG
Trunk configuration > General
Server certificate: UAG computer default certificate
Application Properties > Web Servers
"HTTP Port" checked with value 80
In this case (End User --HTTPS--> UAG --HTTP--> CAS), automatic redirection to /owa/ does not work after authentication. The end user must modify manually the Url to include /owa/.
I created good certificates and configured a full HTTPS chain from End User to Exchange CAS. In this case, redirection is working fine.
Thx
Microsoft