jquery – jqgrid中子网格的postData无法正常工作？

嗨我有一个带有子网格的jqgrid,它调用了一个servlet.
我正在使用POST向servlet发送一些数据,但是在调用子网格时不会发送相同的数据.这是我的JS：

$("#testsTable").jqGrid({
  mtype: "POST",url: "GetCurrentStatusServlet",postData: {BuildPath :"C:\\Test\\01"},datatype: "xml",colNames:['TESTCase Name','Last update','Status'],colmodel:[
      {name:'name',index:'name',width:90},{name:'lastupdate',index:'lastupdate',width:100},{name:'status',index:'status',width:80,align:"right"}   
     ],rowNum:10,autowidth: true,rowList:[10,20,30],pager: $('#pager1'),sortname: 'id',viewrecords: true,multiSELEct: true,caption: "Tests",sortorder: "desc",subGrid: true,subGridUrl : "GetCurrentStatusServlet",subGridModel: [ {
       name:  ['TESTCase Name',width : [100,200,80],params: ['name']}]
 }).navGrid('#pager1',{edit:false,add:false,del:falsE});

那么我怎样才能将postData也发送到子网格servlet？有没有办法指定subgridPostData？
谢谢.

$("#testsTable").jqGrid({
    ...
    subGrid: true,subGridUrl: "GetCurrentStatusServlet",subgridPostData: {foo: "bar"},serializeSubGridData: function(postdata) {
        return $.extend(postdata,this.p.subgridPostData);
    },...
});