optical out on ROG strix B350 F

[Willfal]

hey folks, hopefully someone can shed some light on my problem.

 

finished my ryzen build and everything seems to be working well...bar my audio issue. the rear io has optical out which i want to use... maybe i'm being thick, but it doesn't seem to be in my playback devices. 

 

ive downloaded all the drivers from the Asus site for my mobo, i dont know what else to do 

 

Headset i'm using is Astro A50 Gen 1 and the sound at the moment is being carried to the tx via usb, which i dont want. 

 

attached some images to show my rear audio ports, the astro set up guide and what i see in my playback devices. 

 

please help.

 

 

 

 

[Willfal]

in the 3rd pic of my playback devices ive tried setting "realtek digial output" as the default but nope... no sound