securing wcf service with membership provider

See more:

C#

.NET

WCFServices

hi guys ,
i have a WCF service & i configured it to be authenticated with asp.net membership provider but i try now to add it as a service reference to web application but it get me error "there is error downloading the metadata......" & of course u know the rest of the syntax error

first how can i solve this ?

secondly do i have to create a certificate to make this work ??

here's part of my web config of the WCF service>>>>

<system.serviceModel>
    <bindings>
      <wsHttpBinding>
        <binding name="WsHttpBinding">
          <security mode="TransportWithMessageCredential">
            <transport clientCredentialType="None" />
            <message clientCredentialType="UserName" />
          </security>
        </binding>
      </wsHttpBinding>
    </bindings>
    <services>
      <service behaviorConfiguration="ServiceBehaviour" name="TestAuthonticationService.Service">
        <endpoint address="" binding="wsHttpBinding" bindingConfiguration="WsHttpBinding"
          contract="TestAuthonticationService.IService">
          <identity>
            <dns value="localhost" />
          </identity>
        </endpoint>
        <endpoint address="mex" binding="mexHttpsBinding" bindingConfiguration=""
          contract="IMetadataExchange" />
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior name="ServiceBehaviour">
          <serviceMetadata httpGetEnabled="true" httpsGetEnabled="true" />
          <serviceDebug includeExceptionDetailInFaults="false" />
          <serviceCredentials>
            <userNameAuthentication userNamePasswordValidationMode="MembershipProvider"
              membershipProviderName="AspNetSqlMembershipProvider" />
          </serviceCredentials>
        </behavior>
      </serviceBehaviors>
    </behaviors>