Andrew:

Knowing the file naming convention gives a programmer a starting point for the specific file types you mentioned but they would still need to extract this data from the TIFF files, including converting them to PDF documents. Something we have significant experience with.

As the original poster didn't mention what types of documents where in the TIFF files, are there naming convention for;

Payable Invoices, Credit Notes, & Payments?

PO's, Receipts, Returns, and Misc documents applicable to them that you could attach to those transactions with DocStore? Not to mention the Vendor invoice? Which would then lead to the invoice and supporting PO being attached to the AP Transaction.

I don't believe these exist but I don't believe that would prevent us from being able to modify the data to include a properly structured DocStore link for existing transactions.