eiru_payslip_payments/view/payslip_payments.xml

<?xml version="1.0" encoding="UTF-8"?>
<openerp>
	<data>
        <record id="view_eiru_payslip_payments" model="ir.ui.view">
            <field name="name">view.eiru.payslip.payments</field>
            <field name="model">hr.payslip.run</field>
            <field name="inherit_id" ref="hr_payroll.hr_payslip_run_form"/>
            <field name="arch" type="xml">
                <label for="name" position="before">
                    <div class="oe_right oe_button_box eiru-payslip-payments" attrs="{'invisible': [('state','!=','close')]}"></div>
                </label>
            </field>
        </record>
		<!--ADD botton en  payslip -->
		<record id="view_eiru_payment_payslip_unity" model="ir.ui.view">
			<field name="name">view.eiru.payment.payslip.unity</field>
			<field name="model">hr.payslip</field>
			<field name="inherit_id" ref="hr_payroll.view_hr_payslip_form"/>
			<field name="arch" type="xml">
				<xpath expr="//div[@class='oe_title']"  position="before">
					<div class="oe_right oe_button_box payslip-payment-unity" attrs="{'invisible': [('state','!=','done')]}"></div>
				</xpath>
			</field>
		</record>
	</data>
</openerp>