I'm working under odoo v8, and i'm trying to pass the client_order_ref from sale orders to delivery orders. I could create a new field on delivery orders, called client_order_ref, but I can't pass the value of this field from sale order to delivery order, my custom field is always empty.

Code of my module:

from openerp.osv import fields, osv

class stock_picking(osv.osv):
        _inherit = "stock.picking"
        _columns = {
                'client_order_ref': fields.char('Reference/Description', copy=True),
        }

class sale_order(osv.osv):
        _inherit = "sale.order"

        def _prepare_order_line_procurement(self, cr, uid, order, line, group_id=False, context=None):
                date_planned = self._get_date_planned(cr, uid, order, line, order.date_order, context=context)
                return {
                        'client_order_ref': order.client_order_ref,  # I tried with 'blabla' instead order.client_order_ref and field is still empty
                        'name': line.name,
                        'origin': order.name,
                        'date_planned': date_planned,
                        'product_id': line.product_id.id,
                        'product_qty': line.product_uom_qty,
                        'product_uom': line.product_uom.id,
                        'product_uos_qty': (line.product_uos and line.product_uos_qty) or line.product_uom_qty,
                        'product_uos': (line.product_uos and line.product_uos.id) or line.product_uom.id,
                        'company_id': order.company_id.id,
                        'group_id': group_id,
                        'invoice_state': (order.order_policy == 'picking') and '2binvoiced' or 'none',
                        'sale_line_id': line.id
                }

The code of my view

<openerp>
<data>
        <record id="client_order_ref_stock_view_picking_form" model="ir.ui.view">
                <field name="name">client.order.ref.stock.view.picking.form</field>
                <field name="model">stock.picking</field>
                <field name="type">form</field>
                <field name="inherit_id" ref="stock.view_picking_form"/>
                <field name="arch" type="xml">
                        <field name="origin" position="before">
                                <field name="client_order_ref"/>
                        </field>
                </field>
        </record>
</data>
</openerp>