EDIT

/**

 * Update the table using an Ajax call

 *  @param {object} oSettings dataTables settings object

 *  @returns {boolean} Block the table drawing or not

 *  @memberof DataTable#oApi

 */

function _fnAjaxUpdate( oSettings )

{

	if ( oSettings.bAjaxDataGet )

	{

		oSettings.iDraw++;

		_fnProcessingDisplay( oSettings, true );

		var iColumns = oSettings.aoColumns.length;

		var aoData = _fnAjaxParameters( oSettings );

		_fnServerParams( oSettings, aoData );

		oSettings.fnServerData.call( oSettings.oInstance, oSettings.sAjaxSource, aoData,

			function(json) {

				_fnAjaxUpdateDraw( oSettings, json );

			}, oSettings );

		return false;

	}

	else

	{

		return true;

	}

}

/**

 * Build up the parameters in an object needed for a server-side processing request

 *  @param {object} oSettings dataTables settings object

 *  @returns {bool} block the table drawing or not

 *  @memberof DataTable#oApi

 */

function _fnAjaxParameters( oSettings )

{

	var iColumns = oSettings.aoColumns.length;

	var aoData = [], mDataProp, aaSort, aDataSort;

	var i, j;

	aoData.push( { "name": "sEcho",          "value": oSettings.iDraw } );

	aoData.push( { "name": "iColumns",       "value": iColumns } );

	aoData.push( { "name": "sColumns",       "value": _fnColumnOrdering(oSettings) } );

	aoData.push( { "name": "iDisplayStart",  "value": oSettings._iDisplayStart } );

	aoData.push( { "name": "iDisplayLength", "value": oSettings.oFeatures.bPaginate !== false ?

		oSettings._iDisplayLength : -1 } );

	for ( i=0 ; i<iColumns ; i++ )

	{

	  mDataProp = oSettings.aoColumns[i].mData;

		aoData.push( { "name": "mDataProp_"+i, "value": typeof(mDataProp)==="function" ? 'function' : mDataProp } );

	}

	/* Filtering */

	if ( oSettings.oFeatures.bFilter !== false )

	{

		aoData.push( { "name": "sSearch", "value": oSettings.oPreviousSearch.sSearch } );

		aoData.push( { "name": "bRegex",  "value": oSettings.oPreviousSearch.bRegex } );

		for ( i=0 ; i<iColumns ; i++ )

		{

			aoData.push( { "name": "sSearch_"+i,     "value": oSettings.aoPreSearchCols[i].sSearch } );

			aoData.push( { "name": "bRegex_"+i,      "value": oSettings.aoPreSearchCols[i].bRegex } );

			aoData.push( { "name": "bSearchable_"+i, "value": oSettings.aoColumns[i].bSearchable } );

		}

	}

	/* Sorting */

	if ( oSettings.oFeatures.bSort !== false )

	{

		var iCounter = 0;

		aaSort = ( oSettings.aaSortingFixed !== null ) ?

			oSettings.aaSortingFixed.concat( oSettings.aaSorting ) :

			oSettings.aaSorting.slice();

		for ( i=0 ; i<aaSort.length ; i++ )

		{

			aDataSort = oSettings.aoColumns[ aaSort[i][0] ].aDataSort;

			for ( j=0 ; j<aDataSort.length ; j++ )

			{

				aoData.push( { "name": "iSortCol_"+iCounter,  "value": aDataSort[j] } );

				aoData.push( { "name": "sSortDir_"+iCounter,  "value": aaSort[i][1] } );

				iCounter++;

			}

		}

		aoData.push( { "name": "iSortingCols",   "value": iCounter } );

		for ( i=0 ; i<iColumns ; i++ )

		{

			aoData.push( { "name": "bSortable_"+i,  "value": oSettings.aoColumns[i].bSortable } );

		}

	}

	return aoData;

}

/**

 * Add Ajax parameters from plug-ins

 *  @param {object} oSettings dataTables settings object

 *  @param array {objects} aoData name/value pairs to send to the server

 *  @memberof DataTable#oApi

 */

function _fnServerParams( oSettings, aoData )

{

	_fnCallbackFire( oSettings, 'aoServerParams', 'serverParams', [aoData] );

}

/**

 * Data the data from the server (nuking the old) and redraw the table

 *  @param {object} oSettings dataTables settings object

 *  @param {object} json json data return from the server.

 *  @param {string} json.sEcho Tracking flag for DataTables to match requests

 *  @param {int} json.iTotalRecords Number of records in the data set, not accounting for filtering

 *  @param {int} json.iTotalDisplayRecords Number of records in the data set, accounting for filtering

 *  @param {array} json.aaData The data to display on this page

 *  @param {string} [json.sColumns] Column ordering (sName, comma separated)

 *  @memberof DataTable#oApi

 */

function _fnAjaxUpdateDraw ( oSettings, json )

{

	if ( json.sEcho !== undefined )

	{

		/* Protect against old returns over-writing a new one. Possible when you get

		 * very fast interaction, and later queries are completed much faster

		 */

		if ( json.sEcho*1 < oSettings.iDraw )

		{

			return;

		}

		else

		{

			oSettings.iDraw = json.sEcho * 1;

		}

	}

	if ( !oSettings.oScroll.bInfinite ||

		   (oSettings.oScroll.bInfinite && (oSettings.bSorted || oSettings.bFiltered)) )

	{

		_fnClearTable( oSettings );

	}

	oSettings._iRecordsTotal = parseInt(json.iTotalRecords, 10);

	oSettings._iRecordsDisplay = parseInt(json.iTotalDisplayRecords, 10);

	/* Determine if reordering is required */

	var sOrdering = _fnColumnOrdering(oSettings);

	var bReOrder = (json.sColumns !== undefined && sOrdering !== "" && json.sColumns != sOrdering );

	var aiIndex;

	if ( bReOrder )

	{

		aiIndex = _fnReOrderIndex( oSettings, json.sColumns );

	}

	var aData = _fnGetObjectDataFn( oSettings.sAjaxDataProp )( json );

	for ( var i=0, iLen=aData.length ; i<iLen ; i++ )

	{

		if ( bReOrder )

		{

			/* If we need to re-order, then create a new array with the correct order and add it */

			var aDataSorted = [];

			for ( var j=0, jLen=oSettings.aoColumns.length ; j<jLen ; j++ )

			{

				aDataSorted.push( aData[i][ aiIndex[j] ] );

			}

			_fnAddData( oSettings, aDataSorted );

		}

		else

		{

			/* No re-order required, sever got it "right" - just straight add */

			_fnAddData( oSettings, aData[i] );

		}

	}

	oSettings.aiDisplay = oSettings.aiDisplayMaster.slice();

	oSettings.bAjaxDataGet = false;

	_fnDraw( oSettings );

	oSettings.bAjaxDataGet = true;

	_fnProcessingDisplay( oSettings, false );

}