rma/crm_rma_advance_location/claim_rma_view.xml

<?xml version="1.0"?>
<openerp>
    <data>
    <record model="ir.ui.view" id="crm_claim_rma_form_view">
        <field name="name">CRM - Claim product return Form</field>
        <field name="model">crm.claim</field>
        <field name="inherit_id" ref="crm_claim_rma.crm_claim_rma_form_view"/>
        <field name="arch" type="xml">
            <xpath expr="//button[@string='New Delivery']" position="after">
                <button name="%(action_claim_picking_loss)d"
                                string="New Product Loss" states="open"
                                type="action" target="new"
                                context="{'warehouse_id': warehouse_id,
                                    'partner_id': partner_id}"/>
            </xpath>
        </field>
    </record>

     </data>
</openerp>