Hi,

Try this:

<template id="purchase.portal_my_home_purchase" name="Show Purchase Orders" customize_show="True" inherit_id="portal.portal_my_home" priority="25">
  <xpath expr="//div[hasclass('o_portal_docs')]" position="inside">
      <t t-call="portal.portal_docs_entry">
          <t t-set="title">Purchase Orders Changed</t>
          <t t-set="url" t-value="'/my/purchase'"/>
          <t t-set="placeholder_count" t-value="'purchase_count'"/>
      </t>
  </xpath>
</template>

Thanks