[jQuery] Drag a created div by append

Hello!
I have a little problem in Sortables.
When I create a new div using append, I cannot move it using
Sortables.
Other div's (created by 'hand') I can move normally.
Here's my code:
//Btn Add
$('.btn_adicionar').click(function () {
        $("#conteudo_esquerda").append(conteudo_area());
        atualiza_debug();
    });
//Function for data
conteudo_area = function() {
        return '<div id="grupoN" class="drag"> \
    <div class="grupo_titulo"><img src="images/item.png"
alt="Eventos" title="Eventos" width="22" height="22" class="item" /