sScrollY not working

Hi,

I'm using DataTables and FixedColumn (both latest version).
My page generates an HTML table and apply DataTable on it.
Sometimes i need to completely remove the table from the page and destroy de DataTable object. This works fine but after this i generate again my HTML Table and use DataTable again. But my table, if my HTML table have a small number of rows DataTable seems to not use the "sScrollY" attribute and the result is to small.

Sample of code :

totalHeight = $(window).height();
            headerHeight = $('#header').height() + 2;
            footerHeight = $('#footer').parent().height();
            titreModuleHeight = $('#page-heading').parent().height();

            var height = totalHeight - (headerHeight + footerHeight + titreModuleHeight);
            var columnWidth = ($('#header').width()-120)*12/100;

            app.planningTable =  $('#planning-table').dataTable({
                "bDestroy": true,
                "bRetrieve": true,
                "bSort": false,
                "bInfo": false,
                "aaSorting": [],
                "bFilter": false,
                "bPaginate": false,
                "bAutoWidth": false,
                "aoColumnDefs": [
                {
                    "sWidth": columnWidth+"px",
                    "aTargets": [ "_all" ]
                }
                ],
                "sScrollY": (height-125)+"px",
                "sScrollX": "100%",
                "sScrollXInner": ($('#planning-table thead tr:first th').length*columnWidth)+"px",
                "bScrollCollapse": true
            });

            app.fixedColumns = new FixedColumns(app.planningTable,  {
                "sHeightMatch": "auto"
            });

Any ideas ?