I would look at other alternatives. If the end user is serious about an online store, choosing .Store is a bad choice. For example, out-of-the-box, search engines will not be able to index the site for content that is stored in Sage 100. Unless you host it on a web server with 1 Gbps access to Sage 100, it will be very slow.
Sage still sells it because it is all free money and marketing can say they have a web solution. There is no development going into it and support for it doesn't exist. Implementing eBusiness Manager will cost more is hard and soft dollars (lost sales) than spending the upfront money for much better solutions.
4ebm's website has no address or phone number. They really believe in being ""virtual."" When you don't post an address, phone number or even an email address, I wonder if you're for real. ISM dropped their eBusiness practice and enhancements.