purchase_view.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
	<data>
		<record id="ir_ui_view_purchase_to_sale" model="ir.ui.view">
                        <field name="model">purchase.order</field>
			<field name="inherit_id" ref="purchase.purchase_order_form"/>
			<field name="name">ir_ui_view_purchase_to_sale</field>
			<field name="arch" type="xml">
                                <field name="invoice_method" position="after">                    
                                        <field name="sale_flow" on_change="sale_flow_change(sale_flow, sale_id, warehouse_id)"/>
                                        <field name="sale_id" on_change="sale_flow_change(sale_flow, sale_id, warehouse_id)" attrs="{'invisible':[('sale_flow','in',['normal', 'direct_invoice'])]}"/>
                                        <field name="analytic_account_id" groups="analytic.group_analytic_accounting"/>
                                </field>
			</field>
		</record>

        <record id="ir_ui_view_purchase_to_sale_purchase" model="ir.ui.view">
            <field name="model">purchase.order</field>
            <field name="inherit_id" ref="purchase.view_purchase_order_filter"/>
            <field name="name">ir_ui_view_purchase_to_sale_purchase</field>
            <field name="type">search</field>
            <field name="arch" type="xml">
                <field name="partner_id" position="before">
                    <field name="sale_flow"/>
                </field>
            </field>
        </record>

	</data>
</openerp>