partner_print_voucher/views/voucher_print.xml

<?xml version="1.0" encoding="UTF-8"?>
<openerp>
	<data>
        <record id="views_voucher_print" model="ir.ui.view">
            <field name="name">account.voucher.print</field>
            <field name="model">account.voucher</field>
            <field name="inherit_id" ref="account_voucher.view_vendor_receipt_form"/>
            <field name="arch" type="xml">
                <field name="number" position="before">
					<div class="voucher_button_box oe_right oe_button_box" id="voucher_button_container"></div>
				</field>
            </field>
        </record>
	</data>
</openerp>