WCF Complex JSON INPUT Error (not convertible by QueryStringConverter)

Im having issue geting Complex JSON working as a parameter in my WCF Service.

Using, Microsoft.Net 3.5 SP1 in Visual Studio 2008 SP1

With the following Contract:

[ServiceContract]
public interface IService1
{

    [OperationContract]
    [WebGet(UriTemplate="GetDataUsingDataContract?composite={composite}", 
        BodyStyle=WebMessageBodyStyle.Wrapped, 
        RequestFormat=WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)]
    CompositeType GetDataUsingDataContract(CompositeType composite);

    // TODO: Add your service operations here
}

// Use a data contract as illustrated in the sample below to add composite types to service operations
[DataContract]
public class CompositeType
{
    string boolValue = "true";
    string stringValue = "Hello ";

    [DataMember]
    public string BoolValue
    {
        get { return boolValue; }
        set { boolValue = value; }
    }

    [DataMember]
    public string StringValue
    {
        get { return stringValue; }
        set { stringValue = value; }
    }
}

Using the following URL:

http://localhost:1122/Service1.svc/GetDataUsingDataContract?composite={"BoolValue":"True","StringValue":"Hello"}

With the Enpoint Configuration:

<system.serviceModel>
    <services>
        <service name="WebHTTPBindingExample.Service1" behaviorConfiguration="WebHTTPBindingExample.Service1Behavior">
            <host>
                <baseAddresses>
                    <add baseAddress="http://localhost:8731/Design_Time_Addresses/WebHTTPBindingExample/Service1/"/>
                </baseAddresses>
            </host>
            <!-- Service Endpoints -->
            <!-- Unless fully qualified, address is relative to base address supplied above -->
            <!--<endpoint address="" binding="wsHttpBinding" contract="WebHTTPBindingExample.IService1">