Hi Speziale,
It sounds like you haven’t configured the desk inputs to source from USB (USB-B), check out the KB article below it contains all of the info you require.
http://allen-heath.helpserve.com/Knowledgebase/Article/View/1142/201/how-do-i-route-audio-to-and-from-my-qu-mixer-and-the-daw
Regards
Mike
