jQuery Grid Plugin - jqGrid

Hello

I want ot minimize the traffic between the client and the server. In order to do this, I would like to fetch only the modified row from the server and then update only that row in the grid. I was trying with addRowData but then I lost the 'jsonmap' capability  so I used updateGridRows (it could be great to add jsonreader parameter to addRowData acting in the same way it does in updateGridRows).

This works until I sort the data, then the row modified by updateGridRows is restored to its default value.

What is the correc way to do this?

Thank you very much.