Authorize.net SIM is not currently supported for Powerstore.
You could use Paypal Express Checkout if you don't want to have a digital certificate and accept credit cards on the site.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.