eiru_sale_order/views/template.xml

<openerp>
    <data>
        <template id="eiru_sale_order.assets_backend" name="account_bank_statement_print_assets" inherit_id="eiru_assets.assets">
            <xpath expr="." position="inside">
                <script type="text/javascript" src="/eiru_sale_order/static/src/js/account_bank_statement.js"/>
            </xpath>
        </template>
    </data>
</openerp>