Which board are you running?
If you got the raid created in the BIOS you should have that part right with SATA settings to raid.
set BIOS with SATA Mode = RAID and CSM = Disable
Download the AMD RAIDXpert2 RAID Management Utility and drivers and save drivers to your install media in a folder
When you get to where its looking for drives ans you see none hit F6 or click on load driver.
Point it to where you save the folder with the drivers and select the drivers
Let it load, takes a minute........then you should see your drive
You should be able to get the drivers from your MOBO support page, if not list up your board and Ill see if I can point you to another source.
Just need to know which board it is first.
“Two things are infinite: the universe and human stupidity, I'm not sure about the former” ~ Albert Einstein