Ah man flash is so fucked up.
I have a users list component... and this component doesn't have a removeItem()... but only removeItemAt(index). So I decided to link an array using the dataProvider property. So when I added an item to the array, the list is automatically updated. Then i used splice() to remove items from the array AND SURPRISE SURPRISE, the list component is not updated.
I call this CFUASS - "classical fucked up actionscript shit"... yeah i'm pissed off coz i wasted 30min on something stupid as updating a boring list.