In a remarkably similar post to my last post I noticed that my Wcf-Sql receive locations were failing with the error:

 Could not load file or assembly 'Microsoft.BizTalk.Interop.SSOClient, Version=7.0.2300.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies.  The system cannot find the file specified. 

From my previous run in with this error I suspected that something was misconfigured and targeting the wrong GAC. Again with the help of some internal folks (shout out to Rajkumar and Shaheer) I found the following node was missing from my BTSNTSvc(64).exe.config files:

<startup useLegacyV2RuntimeActivationPolicy="true">
<supportedRuntime version="v4.0" />
</startup>

I'm not sure who or what whacked this (it's correct in TFS and I have the history to prove it!) but without this the Wcf-Sql adapter will attempt to load SSOClient from the .NET 2.0 GAC.