Socket.io: connect to and disconnect from namespaces manually

I have created somes buttons to connect and disconnect from my namespaces:

<div id="message">no message</div>
<button id="disNamespace1" type="button"> Disconnect from namespace1</button>
<button id="disNamespace2" type="button"> Disconnect from namespace2</button>
<button id="conNamespace1" type="button"> connection to namespace1</button>
<button id="conNamespace2" type="button"> connection to namespace2</button>

and I'm handling this buttons like this:

$('#conNamespace1').click(function(ev){
    mySocket = io.connect('http://localhost:1337/namespace1');
    mySocket.on("msg:from:namspace1", function(msg){
        $('#message').text(msg);
    });
});
$('#conNamespace2').click(function(ev){
    mySocket = io.connect('http://localhost:1337/namespace2');
    mySocket.on("msg:from:namspace2", function(msg){
        $('#message').text(msg);
    });
});

$('#disNamespace1').click(function(ev){
    console.log('trying disconnect');
    io.sockets['http://localhost:1337'].disconnect();
});
$('#disNamespace2').click(function(ev){
    io.sockets['http://localhost:1337'].disconnect();
});

My server:

socketNamespace1 = io.of('/namespace1');
socketNamespace2 = io.of('/namespace2');

socketNamespace1.on('connection', function(mySocket){
    console.log('namespace1: new user ');
    mySocket.emit('msg:from:namspace1', 'msg:from:namspace1');
    mySocket.on('disconnect', function(){
        console.log('disconnecting from namespace1');
    }); 
});
socketNamespace2.on('connection', function(mySocket){
    console.log('namespace2: new user ');
    mySocket.emit('msg:from:namspace2', 'msg:from:namspace2');
    mySocket.on('disconnect', function(){
        console.log('disconnecting from namespace2');
    });
});

My first connection and disconnection work great, but when clicking on the connection button for the second time, it doens't works anymores. What is the problem ?