I tried to add the Promise 100 to my system that had just had the WinME upgrade inflicted upon it. I followed the Win95/98 directions that came with the card. Somehow, some files Windows needed to boot got hosed and I decided a total fresh intstall was best at that point.
On the fresh install, I couldn't get the system to see the WD Caviar drive if it was plugged into the Promise. So, I followed the Promise WinNT directions to put the hard drive on the mobo controller, plug in the Promise card empty, install the OS and the Promise driver. Then shutdown, move hd to Promise and reboot. Works fine. The recent WD drives come with ATA66 mode enabled and everything works great. Even WinME.