But I guess you still can use the stereo headphones output going to 2 inputs on your mixer, and record in stereo on your daw on you computer.....right??

Another question:
I have an old Roland XP50 synthesizer/keyboard. Can I use this on the TRIO+, together with guitar parts from my guitars and amp in order to compose a complete song/backing track and finally record everything through DAW (Adobe Audition) in stereo (through headphones output) on my computer and save it there as a wave or mp3-song??
Is such a use and routing possible?