unfortunately I do not completely understand what you are looking for. It is possible to configure a "Login Page" on MWG, which is similar to what Microsoft calls "Form based authentication". But it seems that this is not what you are looking for, since it seems that you are referring to the "Form based authenticaion" of OWA. What is your problem with OWA? Usually I would expect MWG to pass the traffic to the OWA server and present the User with the Login prompt to OWA.
Or did the ISA server allow single-sign on, so your Users did not need to log on to OWA again?
Maybe you can give an example to allow us to help you.
So ISA has a feature to setup Form Based Auth which is what we currently use to handle two-factor auth 1.) AD 2.) RSA SecurID .
We want to migrate this off of ISA and onto the McAfee Webgateway.
I am looking for help in getting this to work. I have installed the rule "Cookie Authentication at Authentication server" and seems to be a good start but it does not handle both Auth servers (AD and Radius).