tlw
Interface sends signal to computer, and through DAW/Amplitube. You'll need to enable track echo if Amplitube's loaded into a DAW to hear what Amplitube is doing.
DAW sends signal back to interface. Not to the stereo outs connected to the monitor, but to another available output. The audio track's output will need to be configured to point directly at that output.
Doubt that is possible using a Presonus Audiobox 2x2. I believe that is why the headphone out was mentioned earlier. The monitors occupy the two available audio outputs from the interface.