About fnServerParams and json

I've got a problem with fnServerParams.
I've seen several discussions about fnServerParams, know that it only support "name/values" pairs.
Here's the thing:
when using fnServerData, we can push any json object(not only "name/values") like this:

//version: Datatables 1.10.4
fnServerData: function (sSource, aoData, fnCallback){
    aoData.push({id:"userId", clientName:"name", address:"xxx"});
}

then how i sent the extra params of any json object(not only like {name:"id", value:"userId"}) with fnServerParams?