Here are a copy of the event codes I'm going off.

# Silver buttons
KEY_SILVER1="0000001a" # Blank
KEY_SILVER2="0000001b" # Change resolution
KEY_SILVER3="0000001c" # User 1
KEY_SILVER4="0000001d" # User 2

# Fn+F? combination
KEY_Fn_F1="00000080" # Sleep
KEY_Fn_F2=("00000010" "00000011") # Wifi toggle
KEY_Fn_F5="0000002*" # Brightness down
KEY_Fn_F6="0000002*" # Brightness up
KEY_Fn_F7="00000016" # Backlight off
KEY_Fn_F8=("00000030" "00000031" "00000032") # XRandR
KEY_Fn_F9="00000012" # Task Manager
KEY_Fn_F10="00000013" # Mute
KEY_Fn_F11="00000014" # Volume Down
KEY_Fn_F12="00000015" # Volume Up

# Other ACPI events
POWER_AC="00000001"
POWER_BAT="00000000"

If you wanted to try and make custom FN keys out of F3 and F4 I think acpi_listen in linux might be the best bet to get those codes.

I'm still trying to understand why the Volume keys functions aren't as easy to spot in the dsdt.