eiru_crm/views/crm_campaign.xml

<?xml version="1.0"?>
<openerp>
    <data>
        <record id="change_crm_marketing_group_view" model="ir.ui.view">
            <field name="name">crm.lead.inherit.form</field>
            <field name="model">crm.lead</field>
            <field name="inherit_id" ref="marketing_crm.view_crm_opportunity_form"/>
            <field name="arch" type="xml">
                <xpath expr="//group[@string='Marketing']" position="replace">
                    <group string="Marketing">
                        <field name="campaign_id" />
                        <field name="medium_id" />
                        <field string="Origen de la oportunidad" name="source_id" />
                    </group>
                </xpath>
            </field>
        </record>

    </data>
</openerp>