Want to use MediaKbdVol+ and MediaKbdVol-

Hi guys. I have a Logitech MK330 wireless keyboard and I'd like to map MediaKbdVol+ and MediaKbdVol- to Nudge Track Volume Up & Down, but when I hit the key in the dialog to add it to the actions, Windows 10 grabs it and turns my system volume up & down and no keystroke reaches Reaper. I've googled the fuck out of this and I've got nothing. Microsoft says that all you have to do is go to Keyboard under the Control Panel, Hardware tab, and turn off "Enable multimedia buttons and onscreen display." Except that there is no such option. I installed Logitech's SetPoint software, and it only allows you to map a handful of keys, not including the multimedia keys.

Surely somebody has run into and solved this problem before, right? Any help?

Thanks.

Want to use MediaKbdVol+ and MediaKbdVol-