Is it possible to buy an iOS Developer Program for an IBC that was formed in Belize?
If you have never enrolled in the developer program, I would budget $99 to start with a personal account to get use to enrolling and how things work.

Since Apple doesn't even operate a web store for Belize, you may run into some roadblocks and have to incorporate there as well as in a country that has an online store. (See - http://store.apple.com/us/browse/open/country_selector)

I can't imagine this making financial sense to set up multiple shell corporations unless you were both funded to the point where $5,000 of startup costs in legal, registration, etc... was already budgeted as well as expecting tens to hundreds of thousands of dollars of revenue.

Basically, start selling your product and if/when you have a huge tax burden, spend some of your gains on professional advice on whether you want to form one or more international corporations.