eiru_invoiceid_voucher/views/account_invoice_view.xml

<?xml version="1.0" encoding="utf-8"?>

<openerp>
    <data>

        <record id="account_invoiced_voucher_view" model="ir.ui.view">
            <field name="name">account.invoiced.voucher.view</field>
            <field name="model">account.invoice</field>
            <field name="inherit_id" ref="account.invoice_tree" />
            <field name="arch" type="xml">
                <field name="date_invoice" position="before">
                        <field name="seq_invoice"/>
                </field>
            </field>
        </record>

        <record id="view_accountinvoices_filter_search2" model="ir.ui.view">
            <field name="name">accountinvoices.filter.search2</field>
            <field name="model">account.invoice</field>
            <field name="inherit_id" ref="account.view_account_invoice_filter" />
            <field name="arch" type="xml">
              <search>
                   <field name="seq_invoice" string="Secuencia"/>
               </search>
            </field>
        </record>

    </data>
</openerp>