ITA - Fattura elettronica - Cassa previdenziale

This module lets you record Italian social security fund contributions (cassa previdenziale) on customer invoices and transmit them correctly in the electronic invoice.

• A new configuration screen, 'Welfare Fund Type Amounts', is available under the Italian e-invoice menu. There you define each fund type with its percentage amount and an optional administration reference. The combination of fund type and amount must be unique.
• On each invoice line you can select one or more welfare fund amounts. A 'Generate Welfare Lines' button appears on the invoice when needed; it creates separate grouping lines that carry the computed welfare amount (percentage applied to the subtotal of the related lines) and copies the account and taxes from the first related line.
• You cannot validate an invoice while welfare lines still need to be regenerated: Odoo blocks it with an error asking you to regenerate them first.
• When the electronic invoice is generated, the welfare data is written into the DatiCassaPrevidenziale section, including fund type, rate, contribution amount, VAT rate, taxable amount, withholding flag, VAT nature code and administration reference. The grouping lines themselves are excluded from the ordinary invoice line list in the XML.

It extends account.invoice, account.invoice.line and the electronic invoice export wizard, and adds the welfare.fund.type.amount model.