I've been able to get IIS 7 with ARR and URL rewrite to work perfectly! Now my problem is, when I go to "http://support.mydomain.com.ph" it goes to my OTRS server perfectly BUT it gives me a browser warning that my browser is too old - when in fact I'm using the latest version of Firefox.
I'm thinking this is because of the URL rewrite or ARR using IIS7's IE classification which in turn gets passed as some sort of header to the OTRS web server.
I don't really know what the problem is but exchange OWA is working properly, main website is working properly, redirect to OTRS is working properly - except the old browser warning.
See screenshot below of latest Firefox and IE6 (running in a VM Win2k3R2). This is all just a learning environment.