WCF Web Service Hosted in SharePoint 2010 browser blank page response - wcf

Question

I'm facing a problem with SharePoint 2010 custom web service.
The service is an SVC installed and deployed on the system: without particular configuration it works but I need to customize the web.config to achieve some security roles.
The problems is that when I try to invoke methods from browser the response is empty.
This is my web.config
<?xml version="1.0"?>
<configuration>
<system.serviceModel>
<services>
<service name="SharePointWCFService.GetListData"
behaviorConfiguration="WCFBasicHttpBinding.Service1Behavior">
<endpoint address="http://address" binding="basicHttpBinding" contract="SharePointWCFService.IGetListData">
<identity>
<dns value="localhost"/>
</identity>
</endpoint>
<endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/>
<endpoint address="http://address" binding="WebHttpBinding" contract="SharePointWCFService.IGetListData" >
<identity>
<dns value="localhost" />
</identity>
</endpoint>
</service>
</services>
<behaviors>
<serviceBehaviors>
<behavior name="WCFBasicHttpBinding.Service1Behavior">
<serviceMetadata httpGetEnabled="true"/>
<serviceDebug includeExceptionDetailInFaults="true"/>
</behavior>
</serviceBehaviors>
</behaviors>
</system.serviceModel>
</configuration>
This is the interface I'm implementing:
[ServiceContract]
public interface IGetListData
{
[OperationContract]
[WebInvoke(Method = "GET", BodyStyle = WebMessageBodyStyle.Bare, ResponseFormat = WebMessageFormat.Json, RequestFormat = WebMessageFormat.Json)]
JSonResult GetJsonResponse(string data);
}
And this the class
[BasicHttpBindingServiceMetadataExchangeEndpointAttribute]
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Required)]
class GetListData : IGetListData
{
private const string Admin_Svc_GetListData = "Admin_Svc_GetListData";
public JSonResult GetJsonResponse(string data)
{
return new JSonResult()
{
Firstname = "MyFirstname",
Lastname = "MyLastname"
};
} // public JSonResult GetJsonResponse(string data)
Do I must declare something different at web.config side?