We have developed a free app for Shopify you could use to integrate EditionGuard with your Shopify store within just a few minutes. Because of Shopify's new revenue model, our app is not listed on the Shopify store. We have chosen to do this in order to keep our prices low. To install the Shopify app, please go to http://shopify.editionguard.com/ to start the install process.
Please see the screencast below for setup instructions.