pos/pos_change_payment/views/view_account_bank_statement.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
Copyright (C) 2015-Today GRAP (http://www.grap.coop)
@author: Sylvain LE GAL (https://twitter.com/legalsylvain)
License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
-->

<openerp><data>

    <record id="view_account_bank_statement_form" model="ir.ui.view">
        <field name="model">account.bank.statement</field>
        <field name="inherit_id" ref="account.view_bank_statement_form" />
        <field name="arch" type="xml">
            <xpath expr="//field[@name='line_ids']/tree/field[@name='amount']" position="after">
                <field name="pos_statement_id" invisible="1" />
                <button name="%(action_pos_switch_journal_wizard)d" string="Switch Journal" type="action" icon="gtk-index" attrs="{'invisible':[('pos_statement_id', '=', False)]}"/>
            </xpath>
        </field>
    </record>

</data></openerp>