What to put in sDom to display lengthmenu with bootstrap

Hi!

Before using Tabletools in my datatable, I have on top of my table: listbox of lines number

"aLengthMenu": [[10, 25, 50, -1], [10, 25, 50, "All"]]

but when I use tabletools like this: http://datatables.net/release-datatables/extras/TableTools/bootstrap.html
it disappears, it remains tabletools buttons and search box

I find that it is caused by the "sDom" value, I don't understand how to configure it!

I want to display the 3 elements: tabletools menu - number lines listbox - search box!