OK, just noticed that I am transforming a Bitmap class that isn't a InteractiveObject, so it will never trigger the MouseEvent's
Don't know if is the case to restrict the addItem($targetObject:DisplayObject, ..) to addItem($targetObject:InteractiveObject, ...) or have a built in DisplayObjectContainer to handle these cases, the same problem could occur when the basics DisplayObjects (like Video, Shape, ...) are added to TransformManager.