How to download PDF for BFB receivables invoices

Summary:

The requirement is to automate the download of the PDF for a BFB receivables invoice

Content (please ensure you mask any confidential information):

BFB receivables invoices cannot be printed using the Print Receivables Transactions job therefore I cannot use the solutions which have been offered in this forum which rely on creating and storing the PDF as an attachment

The receivables > billing > view image button does produce a PDF image for these invoices, so I assume there is some API at work behind that button

Is there any way for me at access the functionality behind the view image button which doesn't require the Print Receivables Transactions job?