I have configured RAID 1 in ML 10 TODAY - 31-01-2018.
Step by step :
Turn on server
Click on delete button or esc button
It will redirect to bios.
Go to advance and select '' CMS CONFIGURATION'' and enable CMS SUPPORT and select boot optin filter and select legacy only
Again back to advance and select ''SATA CONFIGURATION'' & select SATA MODE SELECTION - change to RAID..
Then - scroll down & select -SOFTWARE FEATURE MASK CONFIGURATION & scroll down and change to 4 seconds normal delay.
And save & exit.
Restart the server then keep press on CTRL + I then you can create the RAID :)
I hope it will help you.
Thanks
Shamzi