Hi, I have the same model , with WCE 6.0 and WTNC 7.3.196 and it works ok.
Press Alt+D for diagnostic mode and K for KB test.
Press CTRL+J and verify the hex value. Then the same keys but now with the virtual Keyboard. They should be the same values , if not there is your problem...
Look up this post https://community.ivanti.com/message/106591#106591
You can remap a key to RollUp or RollDw function value. I use the red/green button for this.
More easy to activate the function and only with one key..