Software to change the data format in a field in the PDF Document Properties box

We have PDF documents where we enter a date into the "subject field" in the PDF Document Properties box (open a PDF document, and then click ctrl-D). This field could have a date entered in many ways. For September 4, 2012, the date could be entered either: 1. September 4, 2012 2. 9-4-2012 3. 9-4-12 4. 9/4/12 5. 9/04/12 6. 9/4/2012 7. 2012/4/09 8. 12/4/9 9. September 2012 and more possibilities We need a program that will standardize all of the date formats into a single date format, such as 9-4-2012 The program must be able to look into a folder, and change all of the files in that folder, subfolder, or sub, subfolders, etc. We have millions of files to be changed, so this must work quickly. The project cost will be put into a milestone The project must be completed with 14 days of project award Your project will be cancelled if you do not complete the project in the time allowed, or if you do not respond to messages within 24 hours.