How to create 'Pay to Remove Ads' feature?

I'm still in the early stages of creating, but I was wondering if it would be possible to create this feature (like in Angry Birds).

Could anyone tell or link me to the process of how it's done - so that I can refer back to it at a later date.

Gracias! 

I haven't done it myself using stencyl, but my understanding is

- Make a global boolean defaulted as false, implement the save game functionality.
- In the advertisement display code, check for that boolean while displaying ads.
- Change the value of that boolean when the player does your IAP (keep the ad removal IAP as a non-consumable purchase).
- Make a button to 'redeem IAP' that updates the value of that boolean based on the signed in store account if the player is online.

Thats pretty much it!
Hope this helps..