Here again your favorite Random Dude.
For a long time deploying images to RAID devices can be a bit tricky. After spending several, but several hours troubleshooting with some Precision Tower (PWS T 3640/3630) devices I was actually able to get them to work. Before we start, this ONLY work for machines running the embedded RAID controller from the motherboard that relies on Intel and SATA Operation in the BIOS.
I haven't tested with a PERC (RAID Controller), but it just might be the same.
As you might know, having a machine on RAID On or just RAID in the BIOS is going to present the disks as a volume and Dell WinPE driver pack DON'T contain those drivers and Windows would usually ask you to put the F6 drivers.
For testing purposes I went to the samba of my SDA and checked what drivers were downloaded for the T3640. There I found that they do download some "raid" drivers at \\SDA.ip\drivers_postinstall\dell\windows_10_x64\precision 3640 tower\storage\ktg51_a00-00\windows10-x64\raid
Next I decided to wipe the winpe drivers (\\SDA.IP\drivers\kbe_windows_x64\ ) and put there those "raid" drivers (no EXE) and the nic drivers, did the usual recache and created by new KBE.
After having the new KBE in the SDA I booted my machine and voila the KBE detects my disks!
I already confirmed that it also works for 3630 Tower using the very same KBE.
I hope that this little idea help you as much as it helped me.
Let me know in the comments if you have questions!