Well no: if you are using all the inputs available on the amp's menu system, ie CD, DVD, HDP, TV/CBL, SAT, VCR, DVR and V.AUX you can't add extra ones AFAIK. Although I think you can set the TUNER input to take audio from the EXT. IN, too.
What you can do is double up on one of the inputs: pressing the input button when that input is selected will cycle the audio input through Auto, HDMI, Digital, Analogue and EXT. IN.
You can do the same with video, using the video select button on the main unit and the source select knob, but you can't select HDMI inputs this way.
So this is really only useful for audio-only multichannel sources such as SACD players, or with components having analogue video outs, such as component, S-video and composite.