Yes, you can create a new Order in VM Invoice and than have it sent (or re-sent if you are editing it) though VirtueMart.
If the order is unpaid, VirtueMart usually includes a payment link in it. (e.g. for PayPal)
(however, this may be dependent on a specific payment method; also please note this is fully controlled by VirtueMart, not by VM Invoice)
As I mentioned in
www.artio.net/support-forums/vm-invoice/...er-editing-the-order , we also plan to add the "(Re-)send Order" action to VM Invoice. But that will again just trigger VirtueMart funciton on mailing the actual order to the client.
VM Invoice does not aim to replace the VirtueMart's order compose and mail function.