You will need to select the "7.1 Direct" mode - based on my reading of the manual, you'll go to the DVD input like you would for a normal DVD and then select "7.1D" on the remote to toggle the DVD input from the normal arrangement (which would presumably be one of the digital audio inputs) to the multi-channel analog.

Of course, if you have a player that you use solely for DVD-A/SACD, you could set it up to always use the 7.1 Direct input...