After upgrading to 12.1.3 from 11.5.10.2: How can I obtain the VAT reports?

I've just upgraded and I'm testing. Taxes seems to have been properly migrated so now I'm dealing with reports. I've followed document EMEA VAT reporting and run the program "EMEA VAT: Pre Reporting Process". Last period reported matches the last accounted one, that's why I supposed that output file is empty and log file shows 0 rows updated. The thing is that now I don't know how to get reports from earlier periods since VAT reports now show no information. How about if I need to run those reports again?

Thanks.