flectra/addons/payment_transfer/views/payment_transfer_templates.xml

<?xml version="1.0" encoding="utf-8"?>
<flectra>
    <data noupdate="1">
        <template id="transfer_form">
            <input type="hidden" name="data_set" t-att-data-action-url="tx_url" data-remove-me=""/>
            <t t-if="return_url">
                <input type='hidden' name='return_url' t-att-value='return_url'/>
            </t>
            <input type='hidden' name='reference' t-att-value='reference'/>
            <input type='hidden' name='amount' t-att-value='amount'/>
            <input type='hidden' name='currency' t-att-value='currency.name'/>
        </template>
    </data>
</flectra>