Hello,
I am developing an application for a client who wants to offer mobile top-up products to their customers via their own payment solution (something like PayPal). I know in-app purchases outside AppStore are forbiden, but I also know there are applications that offer these kinds of transactions. For example banking application (https://itunes.apple.com/us/app/m-zaba/id367809781?mt=8) offers their clients to buy mobile top-up products directly from their application and it is charged from their bank accounts. I have personal experience with this app and I know it works. Also I know I can make transactions with my PayPall app and I am pretty sure these don't include AppStore payment mechanisms.
How is this possible with all these in-app purchases rules by Apple? Obviously it is possible, but under which conditions?