jQuery Grid Plugin - jqGrid

i don't know if i Correctly descripted my question in the title ,this is an example:

server response:

{

  "total":2,

   "result":"success",

   "list" :[{

          "id":2,"username":"admin","name":"Administrator","roleId":"admin"

     },{

         "id":1,"username":"root","name":"Root","roleId":"root"

    }],

    "success":true

}

there is no property can match page and total required in jsonReader. so i want to add two properties to this respone object.but i don't know how can i do that.