Changing the receiving address(es) will render the signature(s) invalid.
Thanks for your reply
Could you please explain in more detail? If the signature was not produced from the receiving address, how can changing the receiving address render the signature invalid?
Note that the receiving address here is Apple.
Sorry Im a bit tired atm, but you sign more than just the inputs. I hope this helps -> http://bitcoin.stackexchange.com/questions/3374/how-to-redeem-a-basic-tx