RS150 Audio Pass Through

I just bought a new RS150 and I am trying to set up the 150 so I can use the RCA inputs to pass the audio signal from my Pre-pro through the 150 as the 150 is connected to my amp powering my towers. I want to control the volume with my prepro when watching movies when using the RCA inputs!

Currently I can get the volume from my Prepro through the 150, but I need to use the volume on the 150. This is less than optimal and isn’t going to work for me.

I thought I read you can simply pass the signal through the rose and control everything with the prepro. IS this possible? If so, how do I get to these settings?

Thanks