Not sure about your SACD player. Mine (a Denone 3930CI) does not output multichannel through HDMI or optical cable. To play multichannel SACDs, I have to switch to "Multi Channel" of my receiver which in effect takes all those PLXII or DD out of play. The best is ask Oppo or it's users of help.

Yamaha RXV3800; 2xM80, 2xQS8, VP150 and EP350v3; Panasonic 50" TV; PS3; Harmony One; Denon 3930CI