I have reacently bought a 5.1 multimedia speaker system, more precisely Edifier 5.1 M1550. My motherboard is ASUS H81M-K so I have 3 rear ports(light blue, lime and pink). I connected the front speakers to the lime jack. I have to connect center to the pink one and surround speakers to the blue one. I plugged them in but nothing appears on screen. In the menu of Realtek HD Audio Manager I can click on the lime one and this appears 1 but when I click on the pink one there is no menu 2. Why? I can't change the output.