Ipod Touch 2gen not compatible with Nike C.O.R.E. audio backpack

I have a new ipod touch 2º generation and it doesn´t work with my nike C.O.R.E. audio backpack, this is a back that has an interface to play the ipod and control it with an integrated keypad (check it on Nikeid.com). I have prooved it with the first generation ipod touch and it works, so i don´t understand why this one is not compatible. Any answer? Please help, thanks.