I want to perform with the help of an internal Web service, the AD authentication and put in DMZ available.

As I've read from the thread http://channel9.msdn.com/Forums/TechOff/510686-How-to-call-a-web-services-running-inside-secure-network are three different options possible for call an internal web service from the DMZ.

Can someone confirm me if it's not possible to put a mapping in firewall so that DMZ request is able to call the web service internal. (Dyanmic Routing / Static Routing)

I can not use the VPN option Sad