iRig Pro Duo IO with Cubasis iPad for live use?

Hi all,
New to the forum and Cubasis on iOS so thought I’d ask you guys. I can’t find a video or document referring to my needs, most just show people recording vocals or guitars one at a time. My issue is, I plan on buying an iRig Pro Duo IO to use with Cubasis 3 on iPad for live use. My goal is to have the mic routing through MixBox on track 1 and my guitar through Amplitube on track 2 monitoring at the same time so I can use it live. Is this possible? When I open Cubasis I can’t find anywhere to choose inputs (iRig Duo has two). Right now I just have the iRig HD2 (one input) so I’m not sure if it’s because that only has one input that maybe it’s not giving me options.

If this does not work, does anyone have a preferred way to use Mixbox and Amplitube (or somethings similar vocals/instrument etc) at the the same time for live use with an iRig Pro Duo IO (or multiple input device)? I also have AudioBus 3, but again, I think my main issue is trying to figure out how to use two inputs at the same time on iPad with the iRig Duo. Perhaps it will all make sense once I buy it and plug it in, but I’m trying to verify that I can actually do this before spending hundreds of dollars on something that may not even do what I’m trying to do… Many thanks in advance.