I just bought the same Pioneer AVH-P2400BT less than a month. I got to enjoy all the features everyone is talking about for a couple weeks and it was awesome! And like everyone else, I was naive enough to update my iPhone 4 to iOS 6.
That would be fantastic if Panasonic could come up with some sort of solution since it's unlikely Apple will do anything. I woud happily go back to OS 5 just to regain this feature alone! The thought of buying another iPhone 4 with the older OS on it has even crossed my mind. But with my luck, they're loading OS 6 on everything so I'd be hosed either way.
Keeping my fingers crossed for Pioneer's solution!! 😮