I answered a couple of certificate questions in the C# Windows Store applications forum that you all may find useful:

Provide Client side certificate:

http://social.msdn.microsoft.com/Forums/en-US/winappswithcsharp/thread/0d005703-0ec3-4466-b389-663608fff053

Include Server certificate in manifest so application can
trust an non-trusted or self-issued server certificate:

http://social.msdn.microsoft.com/Forums/en-US/winappswithcsharp/thread/5ec17748-8980-4714-b25a-c3c9192bbefc

 

Great video describing SelfSigned certs and embedding it in an app:

http://channel9.msdn.com/Events/Build/2012/3-127  See at 0:36 - 0:42 for the SSL part.