sale_order.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
    Copyright (C) 2016 Akretion (http://www.akretion.com/)
    @author Alexis de Lattre <alexis.delattre@akretion.com>
    The licence is in the file __openerp__.py
-->

<openerp>
<data>


<record id="view_order_form" model="ir.ui.view">
    <field name="name">account_banking_mandate_sale.sale_order.form</field>
    <field name="model">sale.order</field>
    <field name="inherit_id" ref="account_payment_sale.view_order_form"/>
    <field name="arch" type="xml">
        <field name="payment_mode_id" position="after">
            <field name="commercial_partner_id" invisible="1"/>
            <field name="mandate_id"
                domain="[('partner_id', '=', commercial_partner_id), ('state', 'in', ('draft', 'valid'))]"/>
        </field>
    </field>
</record>


</data>
</openerp>