ITA - Fattura elettronica - Emissione - OSS

This is a technical integration module that connects the OSS (One Stop Shop) tax management with the Italian electronic invoice export. It installs automatically when both the Italian e-invoice and OSS modules are present.

When you generate an OSS tax through the OSS wizard, the module automatically assigns the Italian tax nature code 'N3.2' (not subject to VAT) to the new tax. This ensures the tax is correctly classified for Italian e-invoicing.

When exporting an invoice to the FatturaPA XML format, the module changes how tax summary lines are built. For taxes linked to an OSS country and having a nature code, the VAT rate is forced to 0.00 and the tax amount to 0.00, while the taxable amount and the nature code are still reported. This matches the Italian rules for OSS transactions.

On each invoice line, if the tax is an OSS tax with a nature code, the VAT rate shown is 0.00 instead of the actual rate, and an additional information block is added with type 'OSS' and the real tax rate as reference text.

The module affects the OSS tax creation wizard (l10n.eu.oss.wizard) and the FatturaPA export wizard (wizard.export.fatturapa), and modifies the invoice XML templates used for electronic invoicing. No new menus or screens are added; the changes happen behind the scenes during tax setup and invoice export.