mute key is not tested by "System Testing"

I'm running checkbox-gtk on Clevo D4J (model), D410J (product code) from Ubuntu 11.10 32-bit in LiveCD mode. I

I have selected to test all the hotkeys. Tests were only run against volume up/down and multimedia keys. The report looks like as follows:

 keys/brightness not required on this system Job requirements not met.
 keys/volume PASSED
 keys/mute not required on this system Job requirements not met.
 keys/battery-info not required on this system Job requirements not met.
 keys/wireless not required on this system Job requirements not met.

This keyboard have the following extra keys:
Fn+F3: mute
Fn+F4: sleep
Fn+F5: volume down
Fn+F6: volume up
Fn+F7: switch video mode
Fn+F8: brightness up
Fn+F9: brightness down
Mail key
Web key
Application key

Mute, volume up and volume down keys are working and they display the feedback about the current volume and mute status on the upper right corner of the screen. Pressing sleep button starts putting the laptop to sleep mode. Pressing the brightness up and brightness down buttons change the brightness of the laptop screen without displaying any feedback on the screen.

If I install evtest I can get key events reported for the mentioned keys, except for brightness up and brightness down:

# evtest
No device specified, trying to scan all of /dev/input/event*
Available devices:
/dev/input/event0: Power Button
/dev/input/event1: Sleep Button
/dev/input/event2: Lid Switch
/dev/input/event3: Power Button
/dev/input/event4: AT Translated Set 2 keyboard
/dev/input/event5: Video Bus
/dev/input/event6: Genius Optical Mouse
/dev/input/event7: PS/2 Mouse
/dev/input/event8: AlpsPS/2 ALPS GlidePoint
Select the device event number [0-8]: 5
Input driver version is 1.0.1
Input device ID: bus 0x19 vendor 0x0 product 0x6 version 0x0
Input device name: "Video Bus"
Supported events:
  Event type 0 (Sync)
  Event type 1 (Key)
    Event code 224 (Brightness down)
    Event code 225 (Brightness up)
    Event code 227 (Switch Video Mode)
    Event code 241 (Video Next)
    Event code 242 (Video Prev)
    Event code 243 (Brightness Cycle)
    Event code 244 (Brightness Zero)
    Event code 245 (Display Off)
Testing ... (interrupt to exit)
Event: time 1325630379.617473, type 1 (Key), code 227 (Switch Video Mode), value 1
Event: time 1325630379.617476, -------------- Report Sync ------------
Event: time 1325630379.617498, type 1 (Key), code 227 (Switch Video Mode), value 0
Event: time 1325630379.617499, -------------- Report Sync ------------
^C
#

# evtest
No device specified, trying to scan all of /dev/input/event*
Available devices:
/dev/input/event0: Power Button
/dev/input/event1: Sleep Button
/dev/input/event2: Lid Switch
/dev/input/event3: Power Button
/dev/input/event4: AT Translated Set 2 keyboard
/dev/input/event5: Video Bus
/dev/input/event6: Genius Optical Mouse
/dev/input/event7: PS/2 Mouse
/dev/input/event8: AlpsPS/2 ALPS GlidePoint
Select the device event number [0-8]: 4
Input driver version is 1.0.1
Input device ID: bus 0x11 vendor 0x1 product 0x1 version 0xab41
Input device name: "AT Translated Set 2 keyboard"
Supported events:
  Event type 0 (Sync)
  Event type 1 (Key)
    Event code 1 (Esc)
    Event code 2 (1)
    Event code 3 (2)
    Event code 4 (3)
    Event code 5 (4)
    Event code 6 (5)
    Event code 7 (6)
    Event code 8 (7)
    Event code 9 (8)
    Event code 10 (9)
    Event code 11 (0)
    Event code 12 (Minus)
    Event code 13 (Equal)
    Event code 14 (Backspace)
    Event code 15 (Tab)
    Event code 16 (Q)
    Event code 17 (W)
    Event code 18 (E)
    Event code 19 (R)
    Event code 20 (T)
    Event code 21 (Y)
    Event code 22 (U)
    Event code 23 (I)
    Event code 24 (O)
    Event code 25 (P)
    Event code 26 (LeftBrace)
    Event code 27 (RightBrace)
    Event code 28 (Enter)
    Event code 29 (LeftControl)
    Event code 30 (A)
    Event code 31 (S)
    Event code 32 (D)
    Event code 33 (F)
    Event code 34 (G)
    Event code 35 (H)
    Event code 36 (J)
    Event code 37 (K)
    Event code 38 (L)
    Event code 39 (Semicolon)
    Event code 40 (Apostrophe)
    Event code 41 (Grave)
    Event code 42 (LeftShift)
    Event code 43 (BackSlash)
    Event code 44 (Z)
    Event code 45 (X)
    Event code 46 (C)
    Event code 47 (V)
    Event code 48 (B)
    Event code 49 (N)
    Event code 50 (M)
    Event code 51 (Comma)
    Event code 52 (Dot)
    Event code 53 (Slash)
    Event code 54 (RightShift)
    Event code 55 (KPAsterisk)
    Event code 56 (LeftAlt)
    Event code 57 (Space)
    Event code 58 (CapsLock)
    Event code 59 (F1)
    Event code 60 (F2)
    Event code 61 (F3)
    Event code 62 (F4)
    Event code 63 (F5)
    Event code 64 (F6)
    Event code 65 (F7)
    Event code 66 (F8)
    Event code 67 (F9)
    Event code 68 (F10)
    Event code 69 (NumLock)
    Event code 70 (ScrollLock)
    Event code 71 (KP7)
    Event code 72 (KP8)
    Event code 73 (KP9)
    Event code 74 (KPMinus)
    Event code 75 (KP4)
    Event code 76 (KP5)
    Event code 77 (KP6)
    Event code 78 (KPPlus)
    Event code 79 (KP1)
    Event code 80 (KP2)
    Event code 81 (KP3)
    Event code 82 (KP0)
    Event code 83 (KPDot)
    Event code 85 (Zenkaku/Hankaku)
    Event code 86 (102nd)
    Event code 87 (F11)
    Event code 88 (F12)
    Event code 89 (RO)
    Event code 90 (Katakana)
    Event code 91 (HIRAGANA)
    Event code 92 (Henkan)
    Event code 93 (Katakana/Hiragana)
    Event code 94 (Muhenkan)
    Event code 95 (KPJpComma)
    Event code 96 (KPEnter)
    Event code 97 (RightCtrl)
    Event code 98 (KPSlash)
    Event code 99 (SysRq)
    Event code 100 (RightAlt)
    Event code 102 (Home)
    Event code 103 (Up)
    Event code 104 (PageUp)
    Event code 105 (Left)
    Event code 106 (Right)
    Event code 107 (End)
    Event code 108 (Down)
    Event code 109 (PageDown)
    Event code 110 (Insert)
    Event code 111 (Delete)
    Event code 112 (Macro)
    Event code 113 (Mute)
    Event code 114 (VolumeDown)
    Event code 115 (VolumeUp)
    Event code 116 (Power)
    Event code 117 (KPEqual)
    Event code 118 (KPPlusMinus)
    Event code 119 (Pause)
    Event code 121 (KPComma)
    Event code 122 (Hanguel)
    Event code 123 (Hanja)
    Event code 124 (Yen)
    Event code 125 (LeftMeta)
    Event code 126 (RightMeta)
    Event code 127 (Compose)
    Event code 128 (Stop)
    Event code 140 (Calc)
    Event code 142 (Sleep)
    Event code 143 (WakeUp)
    Event code 148 (Prog1)
    Event code 155 (Mail)
    Event code 156 (Bookmarks)
    Event code 157 (Computer)
    Event code 158 (Back)
    Event code 159 (Forward)
    Event code 163 (NextSong)
    Event code 164 (PlayPause)
    Event code 165 (PreviousSong)
    Event code 166 (StopCD)
    Event code 172 (HomePage)
    Event code 173 (Refresh)
    Event code 183 (F13)
    Event code 184 (F14)
    Event code 185 (F15)
    Event code 217 (Search)
    Event code 226 (Media)
  Event type 4 (Misc)
    Event code 4 (ScanCode)
  Event type 17 (LED)
    Event code 0 (NumLock)
    Event code 1 (CapsLock)
    Event code 2 (ScrollLock)
  Event type 20 (Repeat)
Testing ... (interrupt to exit)
Event: time 1325629224.051513, type 4 (Misc), code 4 (ScanCode), value 1c
Event: time 1325629224.051526, type 1 (Key), code 28 (Enter), value 0
Event: time 1325629224.051528, -------------- Report Sync ------------
Event: time 1325629288.359966, type 4 (Misc), code 4 (ScanCode), value a0
Event: time 1325629288.359979, type 1 (Key), code 113 (Mute), value 1
Event: time 1325629288.359981, -------------- Report Sync ------------
Event: time 1325629288.452141, type 4 (Misc), code 4 (ScanCode), value a0
Event: time 1325629288.452151, type 1 (Key), code 113 (Mute), value 0
Event: time 1325629288.452153, -------------- Report Sync ------------
Event: time 1325629292.610186, type 4 (Misc), code 4 (ScanCode), value ae
Event: time 1325629292.610195, type 1 (Key), code 114 (VolumeDown), value 1
Event: time 1325629292.610197, -------------- Report Sync ------------
Event: time 1325629292.686990, type 4 (Misc), code 4 (ScanCode), value ae
Event: time 1325629292.687002, type 1 (Key), code 114 (VolumeDown), value 0
Event: time 1325629292.687004, -------------- Report Sync ------------
Event: time 1325629296.480730, type 4 (Misc), code 4 (ScanCode), value b0
Event: time 1325629296.480741, type 1 (Key), code 115 (VolumeUp), value 1
Event: time 1325629296.480744, -------------- Report Sync ------------
Event: time 1325629296.562654, type 4 (Misc), code 4 (ScanCode), value b0
Event: time 1325629296.562667, type 1 (Key), code 115 (VolumeUp), value 0
Event: time 1325629296.562668, -------------- Report Sync ------------
Event: time 1325629318.416771, type 4 (Misc), code 4 (ScanCode), value 81
Event: time 1325629318.416783, type 1 (Key), code 148 (Prog1), value 1
Event: time 1325629318.416785, -------------- Report Sync ------------
Event: time 1325629318.616440, type 4 (Misc), code 4 (ScanCode), value 81
Event: time 1325629318.616451, type 1 (Key), code 148 (Prog1), value 0
Event: time 1325629318.616453, -------------- Report Sync ------------
Event: time 1325629322.112264, type 4 (Misc), code 4 (ScanCode), value b2
Event: time 1325629322.112275, type 1 (Key), code 172 (HomePage), value 1
Event: time 1325629322.112277, -------------- Report Sync ------------
Event: time 1325629322.414321, type 4 (Misc), code 4 (ScanCode), value b2
Event: time 1325629322.414333, type 1 (Key), code 172 (HomePage), value 0
Event: time 1325629322.414334, -------------- Report Sync ------------
Event: time 1325629324.513450, type 4 (Misc), code 4 (ScanCode), value ec
Event: time 1325629324.513461, type 1 (Key), code 155 (Mail), value 1
Event: time 1325629324.513464, -------------- Report Sync ------------
Event: time 1325629324.815515, type 4 (Misc), code 4 (ScanCode), value ec
Event: time 1325629324.815527, type 1 (Key), code 155 (Mail), value 0
Event: time 1325629324.815529, -------------- Report Sync ------------
^C
#

# checkbox-gtk --version
0.12.8