Enable WCF message logging

web.config

<system.diagnostics>
    <sources>
        <source name="System.ServiceModel" 
            switchValue="Critical,Information,ActivityTracing"
            propagateActivity="true">
            <listeners>
                <add name="messages"
                    type="System.Diagnostics.XmlWriterTraceListener"
                    initializeData="c:\inetpub\logs\messages.svclog" />
            </listeners>
        </source>
    </sources>
    <trace autoflush="true" />
</system.diagnostics>