Succinctly, Apple is absolutely horrible to deal with for making apps, and they really do not like 'workarounds' and will ban your app if they get a hint of one.

That being said, here is a way you could potentially make it work out:

1) In your iOS app, charge more than in your android app, to cover the 30% take by Apple.

The creates another problem: it's too expensive.

2) To work around that problem use this: http://playseeds.com/
It's a new in-app-purchases model that cycles the payment money into microloans for people in developing countries, then you get the payback. I think you get the payment right away as if it's a normal payment (i.e. all the loan, and payback etc. happens in the background without you being affected). That payment model greatly increases user willingness to make a initial and repeated purchase.

Best of luck

Lee