Wcf – Silverlight WCF Service Reference “The given key was not present in the dictionary”

Question:

I Have a WCF test Service with a reference (.net 3.5) on Silverlight application and when i make an instance

ServiceReference1.Service1Client client = new Service1Client();

i have the following error:

"The given key was not present in the dictionary."

The service is correct and in web.config i have something like this

<client>
        <endpoint address="http://localhost:49955/Service1.svc" binding="wsHttpBinding" bindingConfiguration="WSHttpBinding_IService1" contract="ServiceReference1.IService1" name="WSHttpBinding_IService1">
            <identity>
                <dns value="localhost" />
            </identity>
        </endpoint>
</client>

In a NON silverlight application reference works like a sharm….some ideas to fix it?

PS: the service is a default service:

[ServiceContract]
public interface IService1
{
    [OperationContract]
    void DoWork();
}

public class Service1 : IService1
{
    public void DoWork()
    {
    }
}

MORE INFO

{System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
at System.ThrowHelper.ThrowKeyNotFoundException()
at System.Collections.Generic.Dictionary2.get_Item(TKey key)
at System.ServiceModel.Configuration.ServiceModelSectionGroup.get_Client()
at System.ServiceModel.Description.ConfigLoader.LookupChannel(String configurationName, String contractName, Boolean wildcard)
at System.ServiceModel.Description.ConfigLoader.LoadChannelBehaviors(ServiceEndpoint serviceEndpoint, String configurationName)
at System.ServiceModel.ChannelFactory.ApplyConfiguration(String configurationName)
at System.ServiceModel.ChannelFactory.InitializeEndpoint(String configurationName, EndpointAddress address)
at System.ServiceModel.ChannelFactory1..ctor(String endpointConfigurationName, EndpointAddress remoteAddress)
at System.ServiceModel.EndpointTrait1.CreateSimplexFactory()
at System.ServiceModel.EndpointTrait1.CreateChannelFactory()
at System.ServiceModel.ClientBase1.CreateChannelFactoryRef(EndpointTrait1 endpointTrait)
at System.ServiceModel.ClientBase1.InitializeChannelFactoryRef()
at System.ServiceModel.ClientBase1..ctor()
at SilverlightApplication2.ServiceReference1.Service1Client..ctor()
at SilverlightApplication2.MainPage.MainPage_Loaded(Object sender, RoutedEventArgs e)
at MS.Internal.CoreInvokeHandler.InvokeEventHandler(Int32 typeIndex, Delegate handlerDelegate, Object sender, Object args)
at MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventName)}