Lo siento, he probado eso y no se por que tampoco me funciona. Yo creo que no se ponerlo bien. Pongo aquí mi código por si a alaguien se le ocurre una solución.
Gracias
//función FX fadeIn
alfa = function (clip) {
this.createEmptyMovieClip("loop", 3);// creamos un clip de pelicula para hacer un loop
loop.onEnterFrame = function() {
clip._alpha += 10;
if (clip._alpha>=100) {
delete loop.onEnterFrame;// eliminar loop
}
};
};
this.createTextField("porcentaje", 2, 40, 111.4, 198.9, 20.

;
this.createTextField("porcentaje1", 3, 310, 111.4, 198.9, 20.

;
this.createTextField("porcentaje2", 4, 580, 111.4, 198.9, 20.

;
porcentaje.border = true;
porcentaje1.border = true;
porcentaje2.border = true;
this.image_mc._alpha = 0;
this.image1_mc._alpha = 0;
this.image2_mc._alpha = 0;
var mclListener:Object = new Object();
mclListener.onLoadStart = function(target_mc:MovieClip) {
target_mc.startTimer = getTimer();
};
mclListener.onLoadInit = function(target_mc:MovieClip) {
target_mc._width = 250;
target_mc._height = 250;
};
var image_mcl:MovieClipLoader = new MovieClipLoader();
image_mcl.addListener(mclListener);
image_mcl.loadClip("http://www.inm.es/www/wwb/puert/wde0b000.gif", image_mc);
image_mcl.loadClip("http://www.inm.es/www/wwb/puert/wde0b012.gif", image1_mc);
image_mcl.loadClip("http://www.inm.es/www/wwb/puert/wde0b0d1.gif", image2_mc);
var miFormato:TextFormat = new TextFormat();
miFormato.bold = true;
miFormato.font = "Arial";
miFormato.size = 12;
miFormato.color = 0xFF0000;
miFormato.align = "center";
porcentaje.setNewTextFormat(miFormato);
porcentaje1.setNewTextFormat(miFormato);
porcentaje2.setNewTextFormat(miFormato);
this.onEnterFrame = function() {
this.image_mc.percent = ( this.image_mc.getBytesLoaded()/this.image_mc.getBytesTotal())*100;
this.image1_mc.percent1 = ( this.image1_mc.getBytesLoaded()/this.image1_mc.getBytesTotal())*100;
this.image2_mc.percent2 = ( this.image2_mc.getBytesLoaded()/this.image2_mc.getBytesTotal())*100;
if (!isNan(this.image_mc.percent)) {
this.porcentaje.text = "Cargando: "+ Math.round(this.image_mc.percent)+" %";
}
if (!isNan(this.image1_mc.percent1)) {
this.porcentaje1.text = "Cargando: "+ Math.round(this.image1_mc.percent1)+" %";
}
if (!isNan(this.image2_mc.percent2)) {
this.porcentaje2.text = "Cargando: "+ Math.round(this.image2_mc.percent2)+" %";
}
// imagen cargada
// cargamos la función para el fx y eliminamos el campo que muestra el porcentaje
if (this.image_mc.percent == 100) {
this.porcentaje.removeTextField();
alfa(this.image_mc);
delete this.onEnterFrame;
}
if (this.image1_mc.percent1 == 100) {
this.porcentaje1.removeTextField();
alfa(this.image1_mc);
delete this.onEnterFrame;
}
if (this.image2_mc.percent2 == 100) {
this.porcentaje2.removeTextField();
alfa(this.image2_mc);
delete this.onEnterFrame;
}
};