jQuery Grid Plugin - jqGrid

Hello

I would like to add into the filter header another row. For example when I have date - type column I would like to have filter "from" - "to" for both different input.

So I've managed that I have to add another row of class 'ui-search-toolbar' and than add input for specified columns.

But my question is where in sources I can find code to add those inputs into the form sent to the server while requesting data. I'm using here POST method.

Really thanks

btw. If that problem may be solved in easier way (there is possibility to add more inputs for each column in filterToolbar please let me know)