Also, if you want to keybind anything to the main alphabet section of the keyboard, you have to disable the feature called "direct chat" (found in the General tab of the Character Configuration window). This feature automatically moves focus to the chat window whenever you start typing. With it enabled (which is the default for PS3 and PS4), I believe you can use keybinds to function keys, extras like Insert, Home, Page Up/Down, etc., and numpad keys, but any keystrokes in the main section of the keyboard are interpreted as chat text. With the feature disabled, you can use whatever keys you want as keybinds, but have to manually move focus to the chat bar before typing chat text.

But, as greyjj pointed out, it may not provide what you're looking for regardless, due to the limited selection of what can have keybinds. This manual page lists the possibilities (and their defaults) if you scroll about half-way down to the "Keyboard Controls" section.