Hi,
your choice is to either connect the ipod via a digital dock (one that takes a digital signal from the ipod and does not have a DAC in it) to the CDP's DAC via one of the digital inputs (coax, optical or USB going by its specification) or connecting your ipod directly to your amp. You can do that by either a dock with a DAC in it, or with an analogue cable.
The reason behind that is down to what component can take a digital signal (the CDP) and what can take an analogue signal (the amp).