Jquery datatable server side pagination with WCF

Hi, i need help im not able to implement Server side pagination with JQueryDatatable + WCF seb service.
 
I have written Storeprocedure and all required code and i have tested with Handler and Webservice theire it is working as expected but same thing i am trying to implement with WCF Function then it is not working ...
 
I think somthing i miss on WCF OperationContract Or may be when im calling that function..

1. WCF 
 
[OperationContract]        
[WebInvoke(Method = "POST", UriTemplate = "GetEmployees")]       
string GetEmployees(int iDisplayLength, int iDisplayStart, int iSortCol_0, string sSortDir_0, string sSearch); 

public string GetEmployees(int iDisplayLength, int iDisplayStart, int iSortCol_0, string sSortDir_0, string sSearch)        
{}

 ==================
 
2. AJAX
 
$('#tblEmpList').dataTable({               
"paging": true,               
"ordering": true,               
"filter": true,               
"destroy": true,               
"orderMulti": false,               
"serverSide": true,               
"Processing": true,                 
"ajax":               
{                   
"url": "/RouMaster/Services/RouService.svc/rest/GetEmployees",
"type": "POST",                   
"dataType": "JSON" 
},               
"aoColumns": [                   
{                       
"mDataProp": "Id",                       
"visible": true 
},                   
{ "mDataProp": "EmpName" },                   
{ "mDataProp": "Address" },                   
{ "mDataProp": "Phone" }                   
]           
});
 
 But it is not working =========================
 
not going to methods================
 
Next i tryed ===========================
 
 
[OperationContract]        
[WebInvoke(Method = "POST", UriTemplate = "GetSSFPApplicationList?iDisplayLength={iDisplayLength}&iDisplayStart={iDisplayStart}&iSortCol_0={iSortCol_0}&sSortDir_0={sSortDir_0}&sSearch={sSearch}")]        
string GetSSFPApplicationList(int iDisplayLength, int iDisplayStart, int iSortCol_0, string sSortDir_0, string sSearch);        

but values are going 0 always ...


Can any one help me how to do actually with WCF =================

I Am not doing any MVC application its normal Asp.net Application with WCF Webservice ...

Please some one help me to solve this issue.