Z270M Pro4 M.2 Raid configuration

I tried setting up the raid using 2 M.2 NVME drives, I ran through the following steps:

1.     Press F2 or Del during POST to get into BIOS.
2.     Press F6 to Advanced mode.
3.     Select Advanced, Storage Configuration, and set SATA Mode selection from [AHCI] to [Intel RST Premium With Intel Optane System Acceleration (RAID Mode)].
4.     Set Launch Storage OpROM Policy from [Legacy only] to [UEFI only].
5.     Set M2_1 ??RST Pcie Storage Remapping from [Disabled] to [Enabled].
6.     Set M2_2 ??RST Pcie Storage Remapping from [Disabled] to [Enabled].
7.     Press F10 to save configuration change and get into BIOS again.
8.     Select Advanced, Intel(R) Rapid Storage Technology, Create RAID Volume.
9.     Key-in a volume name and press <Enter>, or simply press <Enter> to accept the default name
10.     Select your desired RAID Level and press <Enter>
11.     Select the hard drives to be included in the RAID array and press <Enter>
12.     Select a stripe size for the RAID array and press <Enter>
13.     Select Create Volume and press <Enter> to start creating the RAID array

Everything looks great until I get to windows 10 install which shows the error "Windows can't be installed on this drive" see attached image.

Dear AHoffpauir,

Thank you for posting your query to the ASRock forum.

We have checked, using M.2 x2 building RAID1/0 the Win10 can be installed properly.

Please make sure that you have the BIOS 2.50 updated.
If possible, please try with a different Win10 installation method and try to re-build the RAID to see if it will work.

With thanks,
ASRock TSD

Edited by ASRock_TSD - 31 Aug 2020 at 1:41pm

Dear Ahoffpauir,

Thanks for the reply.

Please fill out the form from the link below to get further assistance from the technical support.
https://event.asrock.com/tsd.asp

With thanks,
ASRock TSD