Can I split system.serviceModel into a separate .config file?

I want to separate my system.serviceModel section of the web.config into a separate file to facilitate some environment settings. My efforts have been fruitless. When I attempt it using this method. The wcf code throws an exception: "The type initializer for 'System.ServiceModel.ClientBase 1 threw an exception. Can anyone tell me what I am doing wrong?

Web.config:

<configuration>
  <system.serviceModel configSource="MyWCF.config" />
  ....

MyWCF.config:

  <system.serviceModel>
    <extensions>
      ...
    </extensions>

    <bindings>
      ...
    </bindings>

    <behaviors>
      ...
    </behaviors>

    <client>
       ...
    </client>

  </system.serviceModel>