I don't believe you can get that information. You would have to write your own function to do it. It should be very simple though. The only time you need a progress bar is when there is a large amount of files involved, so there has to be a loop from 0 to the number of files to process built into your function. Just set your Progress variable to part/whole. (float)#files_processed/#files. Then if you use a TProgressBar, you can set it's Position to your Progress variable.
Chris