#region IPolicyExporter Members
public void ExportPolicy(MetadataExporter exporter, PolicyConversionContext policyContext)
{
  if (exporter == null)
    throw new NullReferenceException("The MetadataExporter object passed to the ExporterBindingElement is null.");
  if (policyContext == null)
    throw new NullReferenceException("The PolicyConversionContext object passed to the ExporterBindingElement is null.");

  XmlElement elem = doc.CreateElement(name1, ns1);
  elem.InnerText = "My custom text.";
  XmlAttribute att = doc.CreateAttribute("MyCustomAttribute", ns1);
  att.Value = "ExampleValue";
  elem.Attributes.Append(att);
  XmlElement subElement = doc.CreateElement("MyCustomSubElement", ns1);
  subElement.InnerText = "Custom Subelement Text.";
  elem.AppendChild(subElement);
  policyContext.GetBindingAssertions().Add(elem);
  Console.WriteLine("The custom policy exporter was called.");
}
#endregion

public class ExporterBindingElementConfigurationSection : BindingElementExtensionElement
{
  public ExporterBindingElementConfigurationSection()
  { Console.WriteLine("Exporter configuration section created."); }

  public override Type BindingElementType
  { get { return typeof(ExporterBindingElement); } }

  protected override BindingElement CreateBindingElement()
  { return new ExporterBindingElement(); }
}

<system.serviceModel>
  <services>
    <service 
      name="Microsoft.WCF.Documentation.StatefulService"
      behaviorConfiguration="addMetadata"
    >
      <host>
        <baseAddresses>
          <add baseAddress="http://localhost:8080/StatefulService"/>
        </baseAddresses>
      </host>
      <endpoint 
        address="http://localhost:8080/StatefulService" 
        binding="customBinding" 
        bindingConfiguration="exporter" 
        contract="Microsoft.WCF.Documentation.IStatefulService" 
      />
      <endpoint
        address="mex"
        binding="mexHttpBinding"
        contract="IMetadataExchange"
      />
    </service>
  </services>
  <behaviors>
    <serviceBehaviors>
      <behavior name="addMetadata">
        <serviceMetadata
           httpGetEnabled="true"
           httpGetUrl=""
         />
      </behavior>
    </serviceBehaviors>
  </behaviors>
  <bindings>
    <customBinding>
      <!-- 
        Use the name attribute of the binding element as 
        the value of the bindingConfiguration attribute in 
        your endpoint.
      -->
      <binding name ="exporter">
        <!-- Use the name attribute of your binding element extension specified below. -->
        <!-- Be certain the order of your custom binding elements is correct. -->
        <exporterBinding />
        <reliableSession/>
        <textMessageEncoding messageVersion="Default" />
        <httpTransport/>
      </binding>
    </customBinding>
  </bindings>
  <extensions>
    <bindingElementExtensions>
      <!-- Use the add element to associate your bindingelement configuration handler and give it a name to use. -->
      <add 
        type="Microsoft.WCF.Documentation.ExporterBindingElementConfigurationSection,PolicyExtensions" 
        name="exporterBinding" />
    </bindingElementExtensions>
  </extensions>
</system.serviceModel>

<wsdl:definitions xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:wsp="http://schemas.xmlsoap.org/ws/2004/09/policy"

  namespaces removed here for clarity...

>
  <wsp:Policy wsu:Id="CustomBinding_IStatefulService_policy">
    <wsp:ExactlyOne>
      <wsp:All>
        <acme 
          b:MyCustomAttribute="ExampleValue"
          xmlns="http://Microsoft/WCF/Documentation/CustomPolicyAssertions"           xmlns:b="http://Microsoft/WCF/Documentation/CustomPolicyAssertions">
           My custom text.
          <MyCustomSubElement>Custom Subelement Text.</MyCustomSubElement>
        </acme>
        <wsrm:RMAssertion xmlns:wsrm="http://schemas.xmlsoap.org/ws/2005/02/rm/policy">
          <wsrm:InactivityTimeout Milliseconds="600000" />
          <wsrm:AcknowledgementInterval Milliseconds="200" />
        </wsrm:RMAssertion>
        <wsaw:UsingAddressing />
      </wsp:All>
    </wsp:ExactlyOne>
  </wsp:Policy>
  <wsdl:import namespace="http://microsoft.wcf.documentation" location="" />