Adding animation to show more rows function

Hi -

How would I add a slideUp/slideDown animation to showing more/fewer rows in datatables? Below is my function for showing all (I am using a link to do so rather than the dropdown):

showAllRows = function() {
var oSettings = $('#theTable').dataTable().fnSettings();
oSettings._iDisplayLength = '-1';
$('#theTable').dataTable().fnDraw();
};

Chaining slideDown() to fnDraw() doesn't work.

Thanks!