Here is my override of the create method :

def create(self, cr, uid, vals, context=None): 

    if context is None:

        context = {} 

    urlll = str(request.httprequest.url)

    if 'sale.order' not in urlll:

        if vals.get('name', '/') == '/':

            vals['name'] = self.pool.get('ir.sequence').get(cr, uid, 'sale.order.web', context=context) or '/'

        if vals.get('partner_id') and any(f not in vals for f in ['partner_invoice_id', 'partner_shipping_id', 'pricelist_id', 'fiscal_position']):

            defaults = self.onchange_partner_id(cr, uid, [], vals['partner_id'], context=context)['value']

            if not vals.get('fiscal_position') and vals.get('partner_shipping_id'):

                delivery_onchange = self.onchange_delivery_id(cr, uid, [], vals.get('company_id'), None, vals['partner_id'], vals.get('partner_shipping_id'), context=context)

                defaults.update(delivery_onchange['value'])

           vals = dict(defaults, **vals)

    ctx = dict(context or {}, mail_create_nolog=True)

    new_id = super(sale_order, self).create(cr, uid, vals, context=ctx)

    self.message_post(cr, uid, [new_id], body=_("Quotation created"), context=ctx)

    return new_id