Get size of external SWF without loading

I am working on a demo using Flash 8 Professional. There is not much inner-activity and I am creating the piece by combining multiple SWF files.

I would like to create a progress bar that represents the progress of the demo as a whole and allows the user to fast-forward or rewind by moving a draggable component of the progress bar.

My problem is that I would like to get the size of the external SWF files without loading them all initially. I don’t have a preferenance over getTotalFrames or getBytesTotal, but I would like the function to be dynamic in that the size is not hard-coded.

Any help would be greatly appreciated.