product_curve_pricelist/views/product_pricelist_item.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>
        <record id="product_pricelist_item_form_view" model="ir.ui.view">
            <field name="name">product.pricelist.item.form</field>
            <field name="inherit_id" ref="product.product_pricelist_item_form_view"/>
            <field name="model">product.pricelist.item</field>
            <field name="arch" type="xml">
                <field name="categ_id" position="after">
                    <field name="product_curve_id" string="Curva"/>
                </field>
            </field>
        </record>
    </data>
</openerp>