Columns can be enabled (default) and disabled from providing the end user the AutoFill option by using either aoColumns or aoColumnDefs and the bEnable option. These two arrays work in exactly the same way has for DataTables.
This example shows how disabling columns counting from the right hand side of the table can be achieved. In this case, the last three columns.
$(document).ready( function () {
var oTable = $('#example').dataTable();
new AutoFill( oTable, {
"aoColumnDefs": [ {
"bEnable": false,
"aTargets": [ -1, -2, -3 ]
} ]
} );
} );