If you check out addons/product/product.py, you'll see that 'seller_ids' is a one2many field pointing to 'product.supplierinfo' from 'product_id'. If you search for product.supplierinfo in addons/product/product_view.xml there are two records that reference it, "product_supplierinfo_form_view" and "product_supplierinfo_tree_view". The first of these is the the one that pops up when you click "Add an item" under suppliers, the second is the table that you are trying to edit. It looks like this:

        <record id="product_supplierinfo_tree_view" model="ir.ui.view">

            <field name="name">product.supplierinfo.tree.view</field>

            <field name="model">product.supplierinfo</field>

            <field name="arch" type="xml">

                <tree string="Supplier Information">

                    <field name="sequence" widget="handle"/>

                    <field name="name"/>

                    <field name="delay"/>

                    <field name="min_qty"/>

                    <field name="company_id" groups="base.group_multi_company" widget="selection"/>

                </tree>

            </field>

        </record>

So what you'd have to do here is create a new module, inherit the "product_supplierinfo_tree_view" by using <field name="inherit_id" ref="product.product_supplierinfo_tree_view">, then add your fields using something like:

<record id="product_supplierinfo_tree_view_inherit" model="ir.ui.view">

    <field name="name">product.supplierinfo.tree.view</field>

    <field name="model">product.supplierinfo<field>

    <field name="inherit_id" ref="product.product_supplierinfo_tree_view">

        <field name="name" position="after">

            <field name="product_name"/>

            <field name="product_code"/>

        </field>

Since those columns are already in the 'product.supplierinfo' you don't even need to add any custom python code to your module.

Hope that helps! Cheers.

----

Alex Gallien

Information Officer LLC

E-mail: agallien@informationofficer.com

Web: www.informationofficer.com