WCF endpointBehaviors extension not picked up when the name param is present?

Question

I am trying to extend my service endpoint behaviour with custom MessageInspector, extension works fine and its picked up, but only if I don’t define the “name” parameter on behaviour tag and don’t define specific behaviorConfiguration on the endpoint. This means I am extending all endpoints and this is what I don’t want. Could anyone please explain me what am I doing wrong?

This config doesn't pick up myBehaviour extension and doesn't fail.

<system.serviceModel>
   <services>
      <service name="testService">
        <endpoint address="http://localhost:9999/TestServiceService"
                  binding="wsHttpBinding"
                  contract="ITestService "
                  behaviorConfiguration="myBehaviour"
                  />
        <endpoint address="mex"
                  binding="mexHttpBinding" 
                  contract="IMetadataExchange"
                  />
      </service>
  </services>
  <behaviors>
      <endpointBehaviors>
        <behavior name="myBehaviour">
          <HeaderForwardExtension />
        </behavior>
      </endpointBehaviors>
  </behaviors>
  <extensions>
     <behaviorExtensions>
        <add name="HeaderForwardExtension" type="Test.Service.HeaderForwardBehavior, Test.Service, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />
     </behaviorExtensions>
  </extensions>
</system.serviceModel>

However removing

behaviorConfiguration="myBehaviour"

and changing behaviour tag so the name is not present

 <behavior>
    <HeaderForwardExtension />
 </behavior>

works just fine.

Thank you