You can do anything if you have the WA plug-ins
If you have eCart you can use those gateways, too. In fact, everything you want to accomplish can be done with the WA plug-ins, and phpMyAdmin (free download). You will have to write some DB tables and code a little by hand, but you can make PowerStore2 into anything you want.
It's an outstanding product for a developer (me) because with the WA plug-ins and the base PowerStore2 I can sell dozens of clients and their sites won't look the same or work the same. This product is really a goldmine for people with the plug-ins.