Proformal invoice on Checkout: Pending?

I am trying to generate a proformal invoince on Checkout: Pending when checkout process is completed by users (And send it via e-mail) and regular invoince after administrator checks Checkout: Completed in the backend. Module generates only regular invoince yet. Would it be possible to make it generate proformal invoinces also? Does every regular invoince generated has already proformal invoice generated too? I only need to send a link to proformal invoince in e-mail, so maybe I can somehow add a token for such a feature.

Any advice would be greatly appreciated!