Use the InvoiceExtension Extension to model this information.

Elements

Element	Description
`Invoice/UBLExtensions/UBLExtension/ExtensionContent/InvoiceExtension/ InvoicedPrepaymentAmount/ID`	Specify the number of the advanced payment invoice in the final invoice.
`Invoice/UBLExtensions/UBLExtension/ExtensionContent/InvoiceExtension/ InvoicedPrepaymentAmount/TaxTotal/TaxSubtotal/TaxableAmount`	Specify the taxable amount for a given tax category of the preceding corresponding advance payment invoice, in the final invoice.
`Invoice/UBLExtensions/UBLExtension/ExtensionContent/InvoiceExtension/ InvoicedPrepaymentAmount/TaxTotal/TaxSubtotal/TaxAmount`	Specify the tax amount for a given tax category of the preceding corresponding advance payment invoice, in the final invoice.
`Invoice/UBLExtensions/UBLExtension/ExtensionContent/InvoiceExtension/ InvoicedPrepaymentAmount/TaxTotal/TaxSubtotal/TaxCategory`	Specify the tax category for each tax breakdown of the preceding corresponding advance payment invoice, in the final invoice.

Restrictions

For Serbian final invoices, if a an advanced payment exists, you must specify these elements,

Example

<ubl:Invoice>
    <cec:UBLExtensions>
        <cec:UBLExtension>
            <cec:ExtensionContent>
                <vrbl:InvoiceExtension>
                    <!-- Code omitted for clarity -->
                    <vrbl:InvoicedPrepaymentAmount>
                        <cbc:ID>AdvanceInvoiceN</cbc:ID>
                        <cac:TaxTotal>
                            <cbc:TaxAmount currencyID="RSD">110</cbc:TaxAmount>
                            <cac:TaxSubtotal>
                                <cbc:TaxableAmount currencyID="RSD">400</cbc:TaxableAmount>
                                <cbc:TaxAmount currencyID="RSD">80</cbc:TaxAmount>
                                <cac:TaxCategory>
                                    <cbc:ID>S</cbc:ID>
                                    <cbc:Percent>20</cbc:Percent>
                                    <cac:TaxScheme>
                                        <cbc:ID>VAT</cbc:ID>
                                    </cac:TaxScheme>
                                </cac:TaxCategory>
                            </cac:TaxSubtotal>>
                            <!-- Code omitted for clarity -->
                         <cac:TaxTotal>
                    </vrbl:InvoicedPrepaymentAmount>
                    <!-- Code omitted for clarity -->
                </vrbl:InvoiceExtension>
            </cec:ExtensionContent>
        </cec:UBLExtension>
    </cec:UBLExtensions>
    <!-- Code omitted for clarity -->
</ubl:Invoice>