You can outsource noncritical tasks like bookkeeping, but the business people must absolutely know how to sell. If they do that, you're in good shape. Of course selling well requires in-depth knowledge of your product, your target market, your industry, etc.
1. What does the business person do in the weeks/months before there is anything to sell?
2. How do you teach people to sell? Judging by the stories coming out of the major incubators pitching to investors is just a matter of iterating on your elevator speech and answering questions until you have sharpened your vision to a sentence or two. How do you formalize that process in a classroom setting?
2. Practice is a huge part of it. I also think its worthwhile to learn about the training programs bigger companies put their employees through. I have a few cd's from http://www.sandler.com/ that have been very helpful. If you have a friend who works in sales, they probably have a bunch of these.
2. Doing 1) correctly will help you to sell empathically. The best way to learn to sell is to begin with a true understanding of the customer's behavior, situation, and pain points, not so much about technique/flair.
What do you think that one can't sell something before it's available?
In some circumstances it's illegal to accept payment before a product is available, but you can always sell.
in the months before the sales guy can work on marketing, sales strategy, market research... building a reputation with the target audience.