Fiscal requirements for data delivery

is already (partly) solved setting the "Reload from Attachment" in Report XML
partly, because this will not solve the problem if the invoice is canceled / altered / confirmed.
Discussion necessary: should reset to draft manipulate (mark as invalid/delete the attachment ?)

http://www.datasystems.at/Systemloesungen/Archivierung/Rechtliches/bao.asp
in short:
Austrian fiscal authorities require that all printed documents (not specified exactly what is a document) must be either reproducible or be stored as original to be delivered on request either by mail or other media (CD, stick)

I was thinking to get a "certificate" (statement) from Tiny that (certain) documents will not be altered if they have reached a certain "state" (done, closed)
The problem I see is that the programs which produce the report may be altered during the legally required storage period and hence stored document may have not the same form and probably not the same content.
consequently I suggest to integrate a function which is triggered by reaching certain states (done, closed...) which produce the needed documents and store them either in OpenERP's document management system or externally on a file system.
IMHO - as most moves are stored/connected to journals it should be sufficient to be able to reproduce and/or store these data (journal, general ledger, inventory, fixed assets, )
I further assume that the requirements of the authorities vary from country to country OpenERP should provide a structure to easily add the necessary reports/csv exports to workflows.