There are a couple of things not duplicated since long time. It's easy to solve: Create the effect with AS and then add the effect back with AS. Here is an example. Make a movieclip and call it clip.
PHP Code:
import flash.filters.BlurFilter;
var 
blurX:Number 30;
var 
blurY:Number 30;
var 
quality:Number 3;
var 
filter:BlurFilter = new BlurFilter(blurXblurYquality);
var 
filterArray:Array = new Array();
filterArray.push(filter);
clip.filters filterArray;
duplicateMovieClip("clip""clip1"1);
clip1._x 200;
clip1.filters filterArray