I am looking for a shopping cart software that will allow creation of a digital product (PDF file), but does not need to have the file uploaded on the server for download until the digital file is purchased. Then when payment goes through, I will manually upload the file to the server and send a link where the customer will be able to log-in and download the file(s).

The reason for this, is that every file will be unique with it's own barcode, but multiple quantities of the product can be purchased.

To better explain, let me give an example.

Front end
Buyer purchases a digital file product - quantity 5 files.

Back end
Order is received -> Files are uploaded -> download link is sent to Buyer.

Buyer receives download link -> logs-in and downloads 5 different files, each with different barcodes.

Any shopping cart software that has this feature?