what i want to do is add a column to product.product table so i create a new object inheriting from product.product , and i also create a new view inheriting from product.product_normal_form_view but the field i have added to product.product not showing in the form view. i can see the itemid field in product_product table. it is so strange , anyone can help me?? many thanks.

here is the code my_product.py

# -*- coding: utf-8 -*-
from openerp.osv import fields, osv
from datetime import datetime 

class ebayerp_product(osv.osv):
    _name = 'product.product'
    _inherit = "product.product"
    _columns = {
        'itemid' : fields.char('eBay ItemID', size=32, readonly=True, invisible=False),
        }
ebayerp_product()

my_product_view.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>
        <record id="product_normal_form_view" model="ir.ui.view">
            <field name="name">product.normal.form.inherit1</field>
            <field name="model">product.product</field>
            <field name="type">form</field>
            <field name="priority" eval="1"/>
            <field name="inherit_id" ref="product.product_normal_form_view"/>
            <field name="arch" type="xml">
                 <sheet position="inside">
                    <label for="ebayitemid"/>
                    <div name="ean">
                        <field name="itemid"/>
                    </div>
                 </sheet>
            </field>
       </record>
    </data>
</openerp>

product_normal_form_view form view (not all code, because not neccessary)

<record id="product_normal_form_view" model="ir.ui.view">
            <field name="name">product.normal.form</field>
            <field name="model">product.product</field>
            <field eval="7" name="priority"/>
            <field name="arch" type="xml">
                <form string="Product" version="7.0">
                    <sheet>
                        <field name="image_medium" widget="image" class="oe_avatar oe_left"/>
                        <div class="oe_title">
                            <div class="oe_edit_only">
                                <label for="name" string="Product Name"/>
                            </div>
                            <h1>
                                <field name="name"/>
                            </h1>
                            <label for="categ_id" class="oe_edit_only"/>
                            <h2><field name="categ_id"/></h2>
                            <div name="options" groups="base.group_user">
                                <field name="sale_ok"/>
                                <label for="sale_ok"/>
                            </div>
                        </div>
                        <div class="oe_right oe_button_box" name="buttons">
                        </div>