code: @Override
  	public E set(int index, E element) {
  		int idx = getRealIndex(index);
  		return super.set(idx, element);
  	}
docs: Replaces the element at the specified position in this Vector with the
  specified element.
  
  @param index
  the index at which the element will be placed; it can be a positive
  number, or a negative number that is smaller than the size of the vector;
  see {@link #getRealIndex(int)}.
  @param element
  the new value to store at the specified index.
  @return
  the previous element at the specified index.
  @see java.util.Vector#set(int, java.lang.Object)