jsonp query length limitation on IIS7

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JSONP

I am trying to pass data across different domain using jsonp.
Code to call my service

$.ajax({
    type: "GET",
    url: window.serviceURL + "CheckWebsite",
    data: {
         domain: domainName, 
         website: sitename 
     },
    dataType: "jsonp",
    contentType: "application/json; charset=utf-8",
    success: function (data) {},
   error: function (jqXHR, textStatus, errorThrown) {
        if (window.console) console.log("Error... " + textStatus + "        " + errorThrown);
    }
});

First i hosted this service on IIS6 and passed data up to length of 3000 and it worked fine,now i moved my service to IIS7 .The service work properly on IIS7 even even but it does not allow me to pass 3000 characters at a time instead the url length is limited to 2000 now. Do i have to make any additional settings for IIS7

Below is my web.config

<configuration><system.web.extensions>
<scripting>
  <webServices>
    <jsonSerialization maxJsonLength="5000" />
  </webServices>
</scripting></system.web.extensions><connectionStrings><add name="connectionString" connectionString="Data Source=sql2\\yukon;Initial Catalog=TMS_20110623;User id=sa; password=sa;" /></connectionStrings><appSettings><add key="connectString" value="Data Source=sql4;Initial Catalog=vbr;User id=sa; password=sa;" /></appSettings><system.web><compilation debug="true" targetFramework="4.0" /><httpRuntime enable="true" maxQueryStringLength="50000" maxUrlLength="100000" maxRequestLength="100000" /></system.web><system.serviceModel><standardEndpoints><webScriptEndpoint><standardEndpoint name="" crossDomainScriptAccessEnabled="true" /></webScriptEndpoint><webHttpEndpoint<standardEndpoint name="" helpEnabled="True" automaticFormatSelectionEnabled="true" />
  </webHttpEndpoint>
</standardEndpoints>
<bindings>
  <webHttpBinding>
    <binding crossDomainScriptAccessEnabled="true">
    </binding>
  </webHttpBinding>
</bindings>
<services>
  <service name="RestService.RestServiceImpl" behaviorConfiguration="ServiceBehaviour">
            <endpoint address="" binding="webHttpBinding" contract="RestService.IRestServiceImpl" behaviorConfiguration="web">
             </endpoint>
  </service>
</services>
<behaviors>
  <serviceBehaviors>
    <behavior name="ServiceBehaviour">
               <serviceDebug includeExceptionDetailInFaults="true" />
    </behavior>
  </serviceBehaviors>
  <endpointBehaviors>
    <behavior name="web">
      <webHttp />
    </behavior>
  </endpointBehaviors>
</behaviors>
 </system.serviceModel><system.webServer>
<modules runAllManagedModulesForAllRequests="true" />
    <defaultDocument>
        <files>
            <add value="Test1.aspx" />
        </files>
    </defaultDocument>
    <httpProtocol>
        <customHeaders>
            <add name="Access-Control-Allow-Origin" value="*" />
        </customHeaders>
    </httpProtocol></system.webServer></configuration>