WCF ExceptionShielding Error ID does not match up with handlingInstanceId passed to Handler

According to http://msdn.microsoft.com/en-us/library/ff649012.aspx:

You can also specify a Source of "{Guid}" to add the current Handling Instance ID to the Fault Contract property.

In your .config file:

<mappings>
    <add source="{Guid}" name="HandlingInstanceId" />
</mappings>

In your ValidationFault FaultContract:

[DataMember]
public Guid HandlingInstanceId { get; set; }

Note: The "{Guid}" source appears to be a special marker for the Handling Instance ID.

See also: http://entlib.codeplex.com/discussions/232049

And, the last 2 entries: http://entlib.codeplex.com/discussions/243558

is message logging will be helpful? If so I guess you need something like this in your config:

<source name ="System.ServiceModel.MessageLogging" 
      switchValue="Verbose, ActivityTracing">        
<listeners>
  <add name="xml" />
</listeners>

Please notice that source name here is 'System.ServiceModel.MessageLogging' and not 'System.ServiceModel'.

For the full example please see this article: http://msdn.microsoft.com/en-us/library/dd788183.aspx

Hope this will help you.