[Moo] 1.2.1 -> 1.2.4 little help needed

[h-a-r-v]

Hi..

So I've used this script like forever already and now after switching
to 1.2.4 it doesn't seem to work. I know the problem is Fx.Style vs
Fx.Tween, but they've got different syntax or something and because
I'm no mootooler, just a designer, I'd appreciate your help converting
this simple script. All it does is making five links smoothly change
font-size in a given div when they're clicked and then store the
chosen setting in a cookie. The original script can be found here:
http://sherwinhermogenes.co.cc/mootools-increase-decrease-font-size/


window.addEvent('domready', function() {
var resize = new Fx.Style('txt', 'font-size', {duration: 500});
                $('fontXXLarge').addEvent('click', function() {
                        resize.start('28,8em');
                        Cookie.set("font-size", "xxlarge"); //save this for 1 
year
                })
                $('fontXLarge').addEvent('click', function() {
                        resize.start('21,6em');
                        Cookie.set("font-size", "xlarge"); //save this for 1 
year
                })
                $('fontLarge').addEvent('click', function() {
                        resize.start('16,8em');
                        Cookie.set("font-size", "large"); //save this for 1 year
                })
                $('fontMedium').addEvent('click', function() {
                        resize.start('12em');
                        Cookie.set("font-size", "medium"); //save this for 1 
year
                })
                $('fontSmall').addEvent('click', function() {
                        resize.start('9,6em');
                        Cookie.set("font-size", "small"); //save this for 1 year
                })
                //check for font size cookie
                if(Cookie.get("font-size") == "xxlarge"){
                        resize.set(28,8);
                }else if(Cookie.get("font-size") == "xlarge"){
                        resize.set(21,6);
                }else if(Cookie.get("font-size") == "large"){
                        resize.set(16,8);
                }else if(Cookie.get("font-size") == "small"){
                        resize.set(9,6);
                }else{
                        //do nothing, leave default
                }
});

Thanks in advance.
Regards