Add New WCF Service

Question

Estou trabalhando com o clearUsernameBinding (http://webservices20.blogspot.com.br/2008/11/introducing-wcf-clearusernamebinding.html) esta funcionando bem, porém sempre que vou criar um novo WCF Service no projeto da o erro que mostra na imagem



mas se eu copiar e colar um que já existe no projeto não tenho problemas, só me da esse erro quando tem dar um Add New Item.

aqui esta meu web.config

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <configSections>
        <section name="clearUsernameBinding" type="WebServices20.BindingExtenions.ClearUsernameCollectionElement, ClearUsernameBinding, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" requirePermission="false"/>
    </configSections>
    <appSettings>
        
    </appSettings>
    <connectionStrings>
        
    </connectionStrings>
    <system.web>
        <compilation debug="true" targetFramework="4.0" />
    </system.web>
    <system.serviceModel>
        <extensions>
            <bindingExtensions>
                <add name="clearUsernameBinding" type="WebServices20.BindingExtenions.ClearUsernameCollectionElement, ClearUsernameBinding, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />
            </bindingExtensions>
        </extensions>
        <bindings>
            <clearUsernameBinding>
                <binding name="myClearUsernameBinding" messageVersion="Soap12"/>
            </clearUsernameBinding>
        </bindings>
        <services>
            <!--Adesoes-->
            <service behaviorConfiguration="SampleServiceBehaviour"
                     name="Syns.WcfServiceHost.Adesoes.AdesaoModalidadeService">
                <endpoint binding="clearUsernameBinding"
                          bindingConfiguration="myClearUsernameBinding"
                          contract="Syns.WcfServiceHost.Adesoes.IAdesaoModalidadeService" />
            </service>
            <service behaviorConfiguration="SampleServiceBehaviour"
                     name="Syns.WcfServiceHost.Adesoes.AdesaoTipoService">
                <endpoint binding="clearUsernameBinding"
                          bindingConfiguration="myClearUsernameBinding"
                          contract="Syns.WcfServiceHost.Adesoes.IAdesaoTipoService" />
            </service>            
        </services>
        <behaviors>
            <serviceBehaviors>
                <behavior name="SampleServiceBehaviour">
                    <serviceMetadata httpGetEnabled="true" />
                    <serviceDebug httpHelpPageEnabled="true" includeExceptionDetailInFaults="true" />
                    <serviceCredentials>
                        <userNameAuthentication userNamePasswordValidationMode="Custom"
                            customUserNamePasswordValidatorType="WebServices20.Validators.MyUserNameValidator, MyUserNameValidator" />
                    </serviceCredentials>
                </behavior>
                <behavior name="">
                    <serviceMetadata httpGetEnabled="true" />
                    <serviceDebug includeExceptionDetailInFaults="false" />
                </behavior>
            </serviceBehaviors>
        </behaviors>
        <serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
    </system.serviceModel>
    <system.webServer>
        <modules runAllManagedModulesForAllRequests="true" />
    </system.webServer>
</configuration>