io.sockets.socket(socket_id).emit() - has no method 'socket'

im running a nodejs server + express + socket.io version 1.0.4 and everything works as expected in my app, but i just cant emit a message from server side to client side via:

socket_server.sockets.socket(socket_id).emit("message", data);

when i try server throws following error:

    TypeError: Object #<Namespace> has no method 'socket'

but i can remember that code worked on my socket.io 0.7./0.8. projects

What am i doing wrong? :(

a snippet out of my app.js (nodejs server):

    var express = require('express');
var app = express();

/* Server Start */
var server = app.listen(8080, function() {
    console.log('Listening on port %d', server.address().port);
});

app.set("view options", {
    layout: false
});
app.use(express.static(__dirname + '/public'));

app.get('/', function(req, res) {
    res.render('index.html');
});

var socket_server = require('socket.io').listen(server);
socket_server.sockets.on('connection', function(client) {
// fire my emits here like: socket_server.sockets.socket(socket_id).emit("msg", data);
}

In 1.0 you should use:

io.sockets.connected[socketid].emit();

to emit to a specific client.

socket_server.sockets.socket(socket_id).emit(); 

has been replaced in socket.io 1.0.