When I used to have a 30 pin audio dock, after a lot of trial and error with cheap ebay adapters, i leant that the genuine ones are the only ones that (seem to) work properly.
Being apple they're massively overpriced.
Found this at K-Mart Kotara. The guy there said it's a clearance item everywhere. So hopefully they're nationwide.
I don't need one, so I left it there if anyone about the area needs it.
Product details here: http://www.apple.com/au/shop/product/MD823AM/A/lightning-to-...
Anyway, a good saving :)