Scroller and fixed columns together

Hello! Did anybody use scroller extension together with fixed columns one?
When trying to apply both extensions, only the header has fixed columns, while the body doesn't.
What am I doing wrong?
I want a simple table with 40 columns (10 fixed) and 20000 rows.
Here is my code:

$(document).ready(function () {
var data = [];
for (var i = 0 ; i < 20000 ; i++) {
data.push([i, i + 1, i + 2, i + 3, i + 4, i + 5, i + 6, i + 7, i + 8, i + 9, i + 10, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i, i]);
}
var oTable = $('#example').dataTable({
data: data,
deferRender: true,
dom: "frtiS",
scrollY: 1000,
scrollX: true,
scrollCollapse: true
});
new $.fn.dataTable.FixedColumns(oTable, {
leftColumns: 10
});
});