WinSCP refreshes the drive list, when a new drive is attached or removed. Maybe your "ram-disk" tool does not notify about the attached drive properly. I've just tested WinSCP with ImDisk and it works as expected. What tool do you use?
Using SoftPerfect RAM Disk, and
you may be right, since i had couple
of win10 blue screen with reboot after i
tried to mound .iso with windows explorer.
Just maybe you test with this one to be sure.
Just updated, and did testing, and
notice that RAM disk with letters A: and B:
are ignored, and not refreshed in the list,
while other assigned letters to the RAM disk
are appearing in the drive list as it should.