Use certificates in WCF client

This is a good tutorial for configure WCF and X.509 certificate authetication.

http://www.codeproject.com/KB/WCF/9StepsWCF.aspx

I have a problem when I have specified X509FindType attribute in clientCertificate element. The problem is that i have write the attribute with first char (X) in uppercase. The correct syntax x in lower case!!!