We just ran into a problem with our application connecting to an Ssl based webservice.
Our app worked fine on our Windows 2003 Server however when we put it in the live environment which was Server 2008, it failed.
After going through the whole shabang, we determined it be the .Net ServicePointManager needing to be set to use SSL3 security protocol.
Oddly enough when checking the protocol in Server 2008, it displayed using Ssl3. However you still need to set it?!