I am having the same problem on Windows 10 x64 with the latest version RST v14.6.
If I roll-back the driver for the controllers to version v12.9 the raid configuration is correctly identified as HDD and I can open the RST GUI (v14.6) .
I guess with the free update to Windows 10 this issue now effects more people than when only Windows 8.x was around.
Are you able to provide an ETA for the fix - it's almost 1 year since the initial post?