Server Certificate button not responding

Hi all, I have server 2003 with IIS 6 and Exchange 2003. I am trying to
change my OWA so that it will work with SSL. I have installed Microsoft's CA
and then went to default web site's properties in IIS manager. The problem I
am having is that when I go to Directory Security and I press Server
Certificate, nothing happens. When I press the Edit button under Secure
Communications, also nothing happens.
(The View Certificate button is grayed out).
Can you please help me out here ?