Check out and authorize or capture only and process payment later

I have a client wanting to review the order and only charge the customer when the product is ready to ship. I realize in powerstore we have the ability to enter inventory quantity and if the item is not in stock it will not allow the customer to purchase. Is there a way that if the item is not in stock the product can still be ordered and the credit card can be approved but not charged? I realize you can manually go to authorize.net to authorize only but trying to figure out how to accomplish this without having to call the client for credit card information. I am guessing even if you have an SSL it is best NOT to store credit card info in the clients database but safest to use authorize.net.... OR if you have an SSL would it be OK to temporarily store that info, owner of the store get's it and makes stores locally then if need be it could be deleted so no credit card info was permanently stored on the server. Any suggestions are welcome. I would be happy to use powerstore or eCart for this project.