I would like to offer a payment service in a RIA app I am developing. The user can order a service (storage of user files in a secured cloud environment). The fee ist calculated from the size of the files. Is there a payment service like PayPal which can be embedded seamlessly in such a RIA application? Is there a standard way / best practice to do it? In my opinion current payment services target pure web sites, not RIA content.
Currently I am using JavaFX as RIA plattform. IMHO with a Flash app you would have the same issues.