X1 15 Denon Audio Receiver

I cannot get my Denon Audio Receiver to work with the X1 15 remote through the cabinet door.  The remote will control the Denon Audio Receiver with the cabinet door open.  The remote will control the Samsung TV and Xfinity box.  How do I get the remote to control the volume (which is routed through the Denon Audio Receiver with the cabinet door closed?  I have a universal remote, but that defeats the purpose to have to use a separate remote for volume.

Thanks,

CJ Williams