I traced that by trying to open the svc file in IE. This gave me a 401.2, which told me that it was a server configuration problem.

today I tested yuor solution, and it was not wiorking as well as a lot of other tests.
So I had the idea to remove most of the settings which are added automatically by VS 2008 (I’m using also 2010).
And I discovered that the problems was resolved mainly having a very simple configuration:

Magically everything started to work correctly, probably the problem is in one or more parameters that have been added by VS.

Hope this will help all the others which are fighting with this absurd issue.

Stefano

Here is a list of steps i did

1a. Created WCF service and exposed it in IIS on Windows 2003 OS
1b. Created WCF test client and it is running in the same machine (Win 2003 OS)
2. Created a server certificate and client certificate using Win 2003 certicate utility. Placed these in Local Machine & Local user in the following places TrustedPeeople/Personal/Trusted Root.
3. Enabled the Security mode as TransportWithMessageCredentials. Authorization is done using certificate.
4. Mapped the server certificate in IIS and enabled these settings in the WebSite which exposes WCF
a. Enabled Require SSL Channel
b. Require Client Certificate
c. Enable client certificate mapping – used 1-1 mapping and mapped the client certificate to my login username/pwd.
5. used httpcfg utitlity to mapp the thumbpring hash to 0.0.0.0 and 0.0.0.0:443 with these switch -m 1 and -f 2
6. I could able to view the .svc file and WSDL file in Internet Explorer. IE pops up a screen to choose my client certificate.. and on choosing wsdl is displayed without any problem.
7. But the said exception comes when i call a contract using the test client which is also running in the same machine & with same login info.

Please let me know where am i missing.