jQuery Grid Plugin - jqGrid

I have different urls for saving the records when it is a new record and when it is an existing record. I am using inlineNav with both add and edit for my grid. I have set the URL as follows :

    var inlineParams =  {
        addParams : {addRowParams : {url : addUrl}},
        editParams : {url : editUrl}
    };

But it seems like it always uses the editURL even when I add a new record and try to save it.

Is there anyway to use different URLs for add and edit in an inlineNav Grid.

Thanks

anupama