eiru_datepay_accountinvoice/views/views.xml

<?xml version="1.0" encoding="UTF-8"?>
<openerp>
	<data>
		<!-- sale.order -->
        <record id="views_eiru_sale_pay_date" model="ir.ui.view">
            <field name="name">eiru.sale.pay.date</field>
            <field name="model">account.invoice</field>
            <field name="inherit_id" ref="account.invoice_form"/>
            <field name="arch" type="xml">
				    <field name="date_invoice" position="after">
                    <field name="date_pay"/>
                    </field>
            </field>
        </record>

				<!-- Model: account.invoice -->
        <record id="view_form_eiru_sale_pay_date" model="ir.ui.view">
            <field name="model">account.invoice</field>
            <field name="inherit_id" ref="account.invoice_tree"/>
            <field name="arch" type="xml">
                <xpath expr="//field[@name='date_invoice']" position="after">
                    <field name="date_pay"/>
                </xpath>
            </field>
        </record>
	</data>
</openerp>