title: Populating the PrimaryIdentity in WCF
body: <p>I'm using simple HTTP headers to pass a token to a WCF service for authentication (The WCF service is required to use the basicHTTPBinding, so I unfortunately cannot use the canned ws-security implementation). I would like to populate the PrimaryIdentity object so the WCF services can examine it to determine the authenticated user.</p>
  
  <p>The issue is that the <code>OperationContext.Current.ServiceSecurityContext.PrimaryIdentity</code> property is read-only at the time I'm trying to populate it. I've tried using SecurityTokenAuthenticators and IAuthorizationPolicy objects to set the identity info, but that route seems to require the use of message-level security (such as always sending in a username and password), which isn't what I want.</p>
  
  <p>Can anyone shed light on how I could set the PrimaryIdentity field?</p>