fade in out

[Osterello]

ciao,
come posso modificare questo actionscript in modo da far visualizzare con il fade in un'immagine mentre quella precedente svanisce col fade out?

Con questo codice funziona ma la seconda immagine appare solo dopo che la prima è scomparsa del tutto lasciando vedere lo sfondo...

//: SETUP VARIABLES
var maxVal = 4;        // max number of fotos
var oldVar = 0;        // keep track of previous random number
var newVar = 0;        // used to load the next image
var si = 0;            // interval variable

//: LOAD THE NEXT IAMGE
function getImage() {
    newVar = Math.floor(Math.random() * maxVal);                                // get random number
    if (newVar == oldVar) {                                                        // if number = old number..
        getImage();                                                                // get a number
    } else {                                                                    // else
        oldVar = newVar;                                                        // set old to new number
        container_mc.loadMovie ("fotos/foto" + newVar + ".jpg");                // load the next image
        container_mc._alpha = 0;                                                // set its alpha to 0
        this.onEnterFrame = function () {                                        // create loop
            if (container_mc._width > 0) {                                        // check that the image has been loaded
                container_mc._x = Stage.width / 2 - container_mc._width / 2;    // center movieclip to stage
                container_mc.onEnterFrame = fadeIn;                                // start fading out
                delete this.onEnterFrame;                                        // delete loop
            }
        }
    }
}

//: FADE IN THE CURRENT MOVIECLIP
function fadeIn () {
    if (this._alpha <= 100) {                    // if the movieclips alpha is greater than 0
        this._alpha += 5;                        // reduce alpha by 5
    } else {                                    // else
        this._alpha = 100;                        // reduce alpha to 0
        delete this.onEnterFrame;                // delete handler
        si = setInterval(fadeOut, 2000);        // after 2 seconds, fade out the movieclip
    }
}

//: FADE OUT THE CURRENT MOVIECLIP
function fadeOut () {
    clearInterval(si);                            // clear the interval variable
    container_mc.onEnterFrame = function() {    // create loop to fade out
        if (this._alpha >= 0) {                    // if the movieclips alpha is greater than 0
            this._alpha -= 5;                    // reduce alpha by 5
        } else {                                // else
            this._alpha = 0;                    // reduce alpha to 0
            delete this.onEnterFrame;            // delete handler
            getImage();                            // load the next image
        }
    }
}

// load first image
getImage();