Dynamic attach event to socket (socket.io)

In this example code "offer" event transmits some data from one client to another through server. Although, it doesn't works now)

//server side
var ioSpace = io.of('/channel_name');
ioSpace.on('connection', function(socket) {
    var calleeID = '1e-hBUBhwhUUQo8pAAAC';

    socket.on('offer', function(data) {
        var callee = io.sockets.connected[calleeID];
        callee.nsp.name = '/channel_name';

        callee.once('answer', function(data) {
            //To do something
        });

        callee.emit('offer', data);
    });
});

This data transmitted to server from second client.

42/channel_name,["answer",<some data>"type":"answer"}]

but event 'answer' don't working.

And this code

callee.nsp.name = '/channel_name';

looks dirty. Anybody know how best to do here?

It task can be solved with another flags/if/else logic, but interesting concrete this approach - get socket with its namespace by id, attach once event to it, send data and waiting answer.

socket.io 1.3.5, node.js 0.12.0.

---

So. After some code and manual reading:

//server side
var ioSpace = io.of('/channel_name');
ioSpace.on('connection', function(socket) {
    var calleeID = '1e-hBUBhwhUUQo8pAAAC';

    socket.on('offer', function(data) {
        var callee = ioSpace.connected[calleeID];

        callee.once('answer', function(data) {
            //To do something
        });

        callee.emit('offer', data);
    });
});