If the WCF binding is using streaming, the body of the trace record will be recorded as "...". This is true for the Oracle LOB Adapters.
For Example:
<E2ETraceEvent xmlns="http://schemas.microsoft.com/2004/06/E2ETraceEvent">
<System xmlns="http://schemas.microsoft.com/2004/06/windows/eventlog/system">
<EventID>0</EventID>
<Type>3</Type>
<SubType Name="Information">0</SubType>
<Level>8</Level>
<TimeCreated SystemTime="2008-01-06T20:54:11.9969961Z" />
<Source Name="System.ServiceModel.MessageLogging" />
<Correlation ActivityID="{9bb37f9e-3e7c-43a1-9a5c-98e5baa327b0}" />
<Execution ProcessName="w3wp" ProcessID="5588" ThreadID="17" />
</System>
<ApplicationData>
<TraceData>
<DataItem>
<MessageLogTraceRecord Time="2008-01-07T09:54:11.9969961+13:00" Source="ServiceLevelReceiveReply" Type="Microsoft.Adapters.AdapterUtilities.AdapterMessage" xmlns="http://schemas.microsoft.com/2004/06/ServiceModel/Management/MessageTrace">
<s:Envelope xmlns:a="http://www.w3.org/2005/08/addressing" xmlns:s="http://www.w3.org/2003/05/soap-envelope">
<s:Header>
<a:Action s:mustUnderstand="1">http://Microsoft.LobServices.OracleDB/2007/03/ADMIN/Package/Example/response</a:Action>
</s:Header>
<s:Body>...</s:Body>
</s:Envelope>
</MessageLogTraceRecord>
</DataItem>
</TraceData>
</ApplicationData>
</E2ETraceEvent>