The test certificate’s subject looked like this:

CN = TestCertName

Whereas the environment certificate’s subject looked like:

CN = CertName
OU = Company Ltd.
O = Company
L = Town
S = County
C = Country Code

All the examples I’ve seen just cover certificates with the CN part. This is straightforward to reference in the WCF config:

<serviceCredentials>
   <serviceCertificate
            storeLocation="LocalMachine"
            storeName="My"
            findValue="CN=TestCertName"
            x509FindType="FindBySubjectDistinguishedName" />
</serviceCredentials>

However, when the certificate subject has multiple parts (i.e. more than just CN), you need to put all of them in the findValue attribute. But how to separate them? I tried several characters – space, comma, semicolon, colon – none worked. The certificate could not be found! Finally I noticed that in the top part of the certificate’s properties window, the values are separated by a comma and a space. Unbelievably, this also applies to the config! How intuitive. So for the “CertName” certificate above, here’s how to reference it in the WCF config:

<serviceCredentials>
   <serviceCertificate
            storeLocation="LocalMachine"
            storeName="My"
            findValue="CN=TestCertName, OU=Company Ltd., O=Company, L=Town, S=County, C=Country Code"
            x509FindType="FindBySubjectDistinguishedName" />
</serviceCredentials>