[Jon]

I added it to skin1/customer/main/checkout.tpl

AFTER:

{if $payment_data.payment_method ne ""}

{capture name=dialog}
{include file="customer/main/customer_details.tpl"}
{/capture}
{include file="dialog.tpl" title=$lng.lbl_payment_details content=$smarty.capture.dialog extra="width=100%"}