ActionScript 3 :: Clearing EventListeners On FileReference Object

I am trying to remove an event listener on a FileReference object by calling a function, but it seems not to be removed, and I do not understand why.

Here is the code:
private function clearFileUploadListeners(file:FileReference, index:String):void {
var dispatchEvent:Function = function(event:Event):void {
dispatch(event.type, event, index); };
file.removeEventListener(Event.COMPLETE, dispatchEvent);
var bool:Boolean = file.hasEventListener(Event.COMPLETE);
if (bool)
trace("ERROR");
}

When I run this code, the trace actually happens. I don't understand why this boolean returns true, when I just tried to remove the eventListener just above! I believe it has to do with the fact that the dispatchEvent function is defined inside another function when I add the listener:

private function upload(file:FileReference, index:String):void {
var dispatchEvent:Function = function(event:Event):void {
dispatch(event.type, event, index); };
file.addEventListener(Event.COMPLETE, dispatchEvent);
}

The problem is that I need to access this "index" variable from the listener, and I can't set it as a global variable as each file has it's own index and it's a burden if I have to extend each event class to keep track of the index (Event, ProgressEvent, ..). I actually found a temporary solution, I am not sure if it is the best! I put my removeListener method actually inside the upload method, but made it a variable. As AS3 allows dynamic object, I attached this method to one of my object, and so I just call the reference to the method when necessary. The event is actually removed.