Debugging is found at Settings > System > Debugging
I'm not sure that will actually help you. It may do, if it doesn't this is what I believe the correct steps would be:
First find out if those buttons are supported by CEC . If they are not you will not be able to map them. If they are you can then worry about working out how to map them.
To find out if they work with the CEC you are going to have to:
1) Disable the CEC adapter in XBMC (this is required if using OpenElec, not sure about Raspbmc). Disable the CEC in XBMC via:
Settings > System > input devices > peripheral > disable the adapter
this will allow you to launch the CEC-client from the command line (if you don't do this it will complain about being locked)
2) SSH into the terminal and run the cec-client (
http://libcec.pulse-eight.com/faq for help on this). Now press any of those buttons. If they cause the terminal to spew out some output it should mean they can be mapped.
3) map the relevant keys a xml file in the userdata folder
EDIT: I'm not sure if step 1 is required. It would be if you were using a pulse eight USB CEC adapter. As this functionality is build into the PI and I have not tested it, I dont know if it is required.