Odoo / Openerp - Create date on customers tree view

Question

I am trying to add the create_date field in my regular Customer Tree view. Since I am new on Odoo or Openerp, I am using the developer mode, and I went to Settings/User Interface/View and I selected the view res.partner. The following code can be edited:

<?xml version="1.0"?> <tree string="Contacts">
                    <field name="name"/>
                    <field name="function" invisible="1"/>
                    <field name="phone"/>
                    <field name="email"/>
                    <field name="user_id" invisible="1"/>
                    <field name="is_company" invisible="1"/>
                    <field name="country" invisible="1"/>
                    <field name="country_id" invisible="1"/>
                    <field name="parent_id" invisible="1"/>
                </tree>

I would like to insert the field "create_date", since this field is avaliable on the database (table res_partner), but this field is not avaliable to be inlcuded here.

Do you know how can I add the create_date in this view, using the developer mode?