arduino Keyboard for OS X

Hi I have done a keyboard using and arduino pro mini and RN42 bluetooth module with HID firmware, everything works fine except the f4 (launch dashboard)and cmd+f3 (shows desktop )shortcuts, they just don't work, I have done other shortcuts to work as mission control (ctrl+up arrow), minimize (cmd+m), expose(ctrl+down arrow), but these.

Anyone have an idea of how can I solve this?