I wasn't using a RAID, but when I wanted to install Win2k to my main drive which was running of a Promise Ultra100, you press F6 right at the beginning of setup when it asks for SCSI controllers.
A few moments later it will ask you to set up SCSI devices.
You press S or something like that to add a SCSI device, then it will ask you for your floppy disk with the SCSI controller's drivers on it.
Stick that in, hit enter, and it will give you a list to choose from, pick the one that is right hit enter, and it will return the screen asking you to set up SCSI devices, only it will have that one listed now.
Press S to add another or Enter to carry on, press enter.
Setup carries on, and Win2k installs the drivers for that SCSI controller and installs all it's files to that array.
I would recommend going to Promise or HighPoint's website and downloading the latest drivers and putting them on a floppy, or you can just use the one that comes with the card.
And remember any add on IDE controller whether RAID or not is treated as SCSI, the drives will show up in device manager as SCSI drives, and the card will show up under SCSI controllers.
This is quite normal, and the standard way Win2k deals with extra IDE ports.
As for when to hit F6, when the CD detects your Win2k CD, it will say:
"Press any key to boot from CD" and give you a 5 count (dots appear) to hit a key. So press enter (or space bar or "the any key"😉, and then a blue scren will pop up that says win2k pro setup.
Last line of the screen is a status bar, as soon as the screen turns blue it's going to say press F6 in that status bar at the bottom.
So just hit F6 basically as soon as your screen turns blue.
I think you have about 1-2 seconds to press it.
If you miss, just hit the reset button on your PC.
(You can hit F6 more than once if it makes you feel better 😉)