One of the trouble I have is, although I was broadcasting data to the other players, I wasn't able to receive anything at all. Thanks to help from the Nextpeer support guys Alexander Mussafi and others, finally got it working by replacing the calls in AppDelegate to as below, and that solves the problem.
What? You game still doesn't have multiplayer capability?! Give Nextpeer a try, you will be surprised how easy it is, and it's free! Plus, with the excellent service from their support guys, any problem of yours will be easily solved in no time! Honestly, I spent a lot more time getting the painful AV Foundation Framework to function properly than adding multiplayer capability to my game.
One major problem solved, now back to the next one in the long list...