title: X509Certificate2: Extensions are missing
body: <p>In C# i'm loading X509Certificate2 objects from an X509Store initialized like so:</p>
  
  <pre><code>        X509Store store = new X509Store("My", StoreLocation.LocalMachine);
          store.Open(OpenFlags.OpenExistingOnly | OpenFlags.ReadOnly);
  </code></pre>
  
  <p>I made my certificate in Openssl and it is set to "Any purpose". So I would expect the X509Certificate2.Extensions to be non-empty and hold the "Server Auth" extension. However, Extensions is always an empty list. Any ideas?</p>