As I mention before on early posting, one year ago approximately, the SAP standard solution does not take the "folio fiscal" as a new document class within the SAP landscape; current SAP solution apporach is to take folio fiscal as a single text within the FI document that cannot be validated or reported!
Most of us have to create Z tables or programs with a plenty number of fields to cover current or future scenarios such as folio fiscal (uuid), RFC, the amount value of the folio fiscal, dates, etc,
Electronic Accounting it should be considered as a sub-module on your scope for the rest of your life cycle. We are not certainly sure whether SAT new rules will be published the next years, so be proactive and generate a custom solution and study the SAT youtube channel to be one step ahead (available only on spanish unfortunately).
You have to save relationship about the folio fiscal on the invoice and the payment document, and some FI documents certainly it should contain more than one folio fiscal.
To take only the UUID on the header text approach its just a limited and workaround solution in my personal opinion.
Unfortunately to have a "Z table approach" even with a automatic upload charge functionality, is not a "functional" also since you have to maintain an additional transaction that are not natural on the document flow (users will usually hate it).
I really some day, SAP re-disign the "standard solution" on the future, but I think there are not plans for this on the short-time. No updates on the SAP notes has been published for months.
Happy Z ABAP programming 