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>