Recurring Billing

I'm looking for a mod that can do recurring billing - note I am not looking for something that integrates in any way with PayPal Recurring Billing, or any other payment gateway recurring billing really. I am hoping there is a mod out there that can just automatically send an invoice on a recurring basis, with a link to my OpenCart system for the recipient to login and pay the invoice as a single payment transaction. Is there anything like that out there?

Thanks.

Danita

Extensions button top right, ask "recurring billing" in store.