Mr816x w/ Cubase 6 - device attenuation to 0dg doesn't work

Hi all,

Hope that somebody can help with this.
I run Cubase 6 on a Mac Pro with Maveriks. I’m trying to use the outs of my mr816x to feed some outboard gear but even though I enter the control panel in Cubase and activate the “set device atenuation to 0db” function nothing happens, and the volume of the mr816x outs are not affected at all.

What may the cause be?