Hello! Currently, the email is only a notification of the invoice so the user comes to your site to view and pay the invoice. Adding an invoice to the email is definitely something we will work to integrate. Recurring payments are not part of the 1.0 version, but as soon as we're done with our Joomla 1.5 updates for our components, we'll be adding this feature and others to DT Billing. The recurring payments will be the first new feature to add, so watch as we'll be releasing a new version very soon! Thanks.