We have configured IIS 6 to accept client certificates and have installed the certificate services on our server. When we go to http://[our site]/CertSrv and request a Web Browser Certificate (client certificate) from IE7/8 on Windows XP and Vista and Windows 7, then issue the cert on the server certificate authority manager, all combinations of the client/OS seem to install the client certificate properly in the personal certificate store.

When we visit our test application that requires client certificates, all IE versions installed in Windows XP propmt for the client certificate and then properly display the page. Uhfortunately, all IE versions installed on Vista and Windows 7 do not prompt for the cert, nor do they automatically send the cert. It's like IE on these operating systems is unaware of the client certificate and it doesn't prompt for it, nor does it send it to the site.

Since everything works as expected, at least on the XP configurations, we assume that IIS6 is correctly configured.

It's been 8 hours with two of us trying to figure this out and we're ready to throw a laptop through a window and "the google" has let us down.

Thanks for anyone who can help.

Mark