1) Make sure that that the new theme has the following file .
layout/reward.xml
template/reward
2) If not there please copy the same from enterprise/layout/reward.xml enterprise/template/reward
3) Include the following in checkout.xml file
<block type=”core/template” name=”checkout.onepage.payment.additional” as=”additional” />
<block type=”core/template” name=”checkout.onepage.payment.methods_additional” as=”methods_additional” />
It should be placed within the payment block
<block type=”checkout/onepage_payment” name=”checkout.onepage.payment” as=”payment” template=”checkout/onepage/payment.phtml”>
<block type=”checkout/onepage_payment_methods” name=”checkout.payment.methods” as=”methods” template=”checkout/onepage/payment/info.phtml”>
<action method=”setMethodFormTemplate”><method>purchaseorder</method><template>payment/form/purchaseorder.phtml</template></action>
</block>
<block type=”core/template” name=”checkout.onepage.payment.additional” as=”additional” />
<block type=”core/template” name=”checkout.onepage.payment.methods_additional” as=”methods_additional” />
</block>