How to disable "Recent" button in TC8000?

Hi, we are trying to change the behaviour of "Home" and "Recent apps" on-screen buttons of TC8000 with Lollipop 5.1.1 Non-GMS. To be specific, we would like to disable these keys in our application. Because devices are Non-GMS version, we cannot use Lock Task mode. And we don't want to use EHS's Kiosk mode because we need to have AppGallery available as well as "Back" key must stay enabled. So we tried to use Profile Manager in EMDK for Android to achieve our goal.

We succeded in disabling the "Home" key using UIManager, but we are unable to disable "Recent" button using KeyMapping manager. We are receiving an error "Unsupported key". We also tried to run "QueryAvailableKeys" profile, which returned only 4 keys, available also in Key Programmer section in Settings. According to documentation on TechDocs, also capacitive buttons should be supported. But I guess that on-screen buttons are not equal to capacitive buttons. Could anyone please confirm that or explain more which keys are we able to change?

 

And finally. Is there any way to disable or hide the recent button, in general and specifically on TC8000?