sale_pricelist_recalculation/wizard/sale_order.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>
      <record id="button_change_pricelist_products" model="ir.ui.view">
        <field name="name">button.change.pricelist.products</field>
        <field name="model">sale.order</field>
        <field name="inherit_id" ref="sale.view_order_form"/>
        <field name="arch" type="xml">
          <field name="pricelist_id" position="replace">
              <field domain="[('type','=','sale')]" name="pricelist_id" groups="product.group_sale_pricelist" on_change="onchange_pricelist_id(pricelist_id,order_line)" options="{'no_create':True}" readonly="1"/>
          </field>

          <field name="pricelist_id" position="after">
              <label for="pricelist_id" string="Actualizar Tarifa"/>
              <div>
                  <button name="%(action_change_pricelist)d" type="action" string="Tarifa" icon="gtk-jump-to"
                        class="oe_button oe_form_button oe_highlight" help="Seleccionar Lista de Precio"
                         attrs="{'invisible': [('state', 'not in', ['draft', 'sent'])]}"/>

              </div>
          </field>
        </field>
      </record>
    </data>
</openerp>