[Plugin: Woocommerce] set names for downloadable file upload

I am trying to change the section in the admin for adding a product. I want to make the downloadable file upload part have 3 set file upload lines. (without having to click the Add File button each time) Each line having a set file name (PDF, epub, mobi) and then of course the file URL upload field next to each one.

For example, line one would be:
Name File URL
PDF: (field for the file name) (Choose File)button

I want the user to have the choice of uploading any or all of the corresponding files without needing to type in the name in the name field. (I want those to default to PDF, ePub or Mobi)

Any Ideas? I have looked at the code, but obviously don’t know enough when it comes to arrays. An example would be so awesome!