Based on a quick review of the linked CodeProject page, your config file seems to be a bit off (as it does not indicate that any endpoints are actually using a client credential type).
The "NewBinding0" specifies clientCredentialType="Certificate" but the article indicates the value should be:
<binding name="NewBinding0">
<security mode="Message">
<message clientCredentialType="UserName"/>
</security>
</binding>
Also, the Service definition only defines a “mex” (metadata) endpoint. You most likely will want to define an wsHttpBinding.. endpoint, which utilizes the corrected binding that specifies clientCredentialType="UserName".
<endpoint address="" binding="wsHttpBinding" bindingConfiguration="NewBinding0"/>
Hope this helps.
Regards,