eiru_inmobiliaria/views/product.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
  <data>
    <record model="ir.ui.view" id="inmobiliaria_product_template">
      <field name="name">inmobiliaria_product_template</field>
      <field name="model">product.template</field>
      <field name="inherit_id" ref="product.product_template_form_view"/>
      <field name="arch" type="xml">
        <xpath expr="//page[@string='Sales']" position="inside">
          <group name="comisiones" string="Comisiones">
            <field name="comision_inmobiliaria"/>
            <field name="comision_vendedor"/>
            <field name="comision_propietario"/>
            <field name="comision_total"/>
          </group>
        </xpath>

        <xpath expr="//page[@string='Sales']" position="after">
         <page string="Datos del Terreno">
           <group name="terreno" string="Datos del Terreno">
             <field name="t_propietario" domain="[('supplier','=',True)]"/>
             <field name="t_nro"/>
             <field name="t_manzana"/>
             <field name="t_lote"/>
             <field name="t_tamanho"/>
             <field name="t_direccion"/>
             <field name="t_estado"/>
             <field name="t_descripcion"/>
           </group>
         </page>
       </xpath>
     </field>
    </record>
  </data>
</openerp>