Tween an array Item

I built a script that will have movieclips populate the stage. In this case a leaderboard.

each movieclip created is positioned and put into an Array.

The problem is getting an array item and being able to tween it

*i'd like to experiment with different tween combinations to get them off the stage. Here is what I got

I'm able to get the clips on the stage...Can't get them off =]

import mx.transitions.Tween;

import mx.transitions.easing.*;

Block = new Array();

var Xposition:Number = 0;

var Yposition:Number = 0;

var stack:Number=Math.ceil(Stage.height/30);

var Numofstacks:Number=Math.ceil(Stage.width/30);

var fadeit:Tween;

var n:Number = 0;

for (r=0; r<(Numofstacks); r++) // 25

{

          Yposition=0;

                    for (c=0; c<(stack); c++) // 3

                    {

                              var particle = this.attachMovie("block","block_"+r+c ,this.getNextHighestDepth());

                              particle._y = Yposition

                              particle._x = Xposition

                              Block = particle._name;

                              //trace(particle._name)

                              Yposition = Yposition + 30;

                              n++

                    }

                    Xposition=Xposition+30

}

var runit = setInterval(effcts, 3000)

function effcts ():Void

{

          trace("go")

          //for (a=0; c<(Block.length - 1); a++) // 3

                    //{

                              fadeit = new Tween(Block[0], "_alpha", Strong.easeOut, 100, 0, 1.5, true);

                    //}

clearInterval(runit);

}