Precision 7710 UEFI Bios and pre-boot does not detect second SSD (NVMe PM951) can't install Windows on it for dual boot

I have a new Precision 7710 with a 2.5 inch 1GB SATA SSD (system boot=Disk0) and a 1GB NVMe PM951 SSD.

I have been attempting to install Windows Server 2012R2 on the second, M.2 SSD (Disk1) into a GPT, NTFS partition.

Since this system has no DVD, I made a bootable UEFI thumb drive with the contents of the .iso installation for Server 2012R2.

The thumb drive boots OK and I can begin installation, but when it comes to choosing the target for installation, the M.2 SSD is not visible in setup.

The M.2 drive is clearly visible inside Windows 10 Pro as the D: drive.

So...I mounted the .iso setup file in Windows 10 and ran setup.exe. The install began and could see the target M.2 drive, and began loading files on the second SSD. It then attempted the first of several restarts that come with this process with the new Server 2012 R2 environment.

It sucessfully modified the Windows Boot Manager before the restart, then restarted, and the setup program gave an error because it could not find the target partition on the second SSD.

The setup environment then modified the Boot Manager to "Windows Setup Rollback" and proceeded to enter an infinite loop, attempting to delete files from the unreachable M.2 drive. I manually choose Windows 10 on the boot menu, and once booted changed Windows 10 back to the default OS.

I've tried several things (turning off Secure boot, changing from UEFI to legacy bios--it won't boot at all that way) , but I can't get that second disk to be visible in the bios or in the preboot environment.

The only place I can access the second SSD is if Windows 10 is already running.

I am trying to replicate a development machine (M6600 that Dell won't repair) that had 3 bootable SSD's.

Any suggestions?

Thanks