Selecting different inputs - Denon RCD-n7

I’ve successfully set up the Denon/Marantz binding for my Denon RCD n7, which is a networked stereo system rather than an AVR. While some of the inputs work, the standard inputs for the binding are labelled ‘AUX1’, ‘AUX2’ etc, whereas by RCD-n7 seems to accept ‘AUXB’, ‘AUXC’. Standard inputs such as ‘TUNER’ work fine. Is there any way I can set up the correct inputs for my device or is that deep within the binding itself?