Audio settings loopback

Got a ASUS Xonar Essence STX where I am used to looping audio from Analog / Headphones 1 to Digital output. I tried through PulseAudio Volume Controller using the command ‘pactl load-module module-loopback’ to load the loopback module yet I only get the option to loop from Stero output and not Headphones 1. Any suggestion what to do?