Success! I used a remote.xml file I found out there and modified it. As in the guides, I created a new text file and renamed it remote.xml, copied it to %appdata%\Roaming\XBMC\userdata\keymaps and simply restarted xbmc/kodi afterwards.
*** EDITED ***
The functionality of the original TV remote buttons is very basic and limited, so my main concern is getting the most important basics available: Volume control and subtitles control, all while keeping some even more basics available such as navigation buttons, so Kodi will remain functional - even for the more advanced uses and menus. So far these are the buttons I found available (should you find others to be available, do tell!):
In the center of the remote, the main big buttons: UP, DOWN, LEFT, RIGHT, OK, BACK, EXIT - These were left mostly untouched by me, except for when playing full screen videos - when you play full screen videos, UP will change or disable subtitles and DOWN will mute.
In the lower section of the remote: STOP, PLAY, PAUSE, SKIPMINUS, SKIPPLUS - were changed in their uses both in the global and full screen videos states. For example, PAUSE will pause when playing a movie, but will pop up information when an item is highlighted. Wherever you are in Kodi, SKIPMINUS and SKIPPLUS will change the volume.
So all you LG TV users out there (I have a 42LM3400-ZA TV), hope the following helps (copy\paste it to your new remote.xml file and modify it according to your needs):
<?xml version="1.0" encoding="UTF-8"?>
<!-- This file contains the mapping of keys (gamepad, remote, and keyboard) to actions within XBMC -->
<!-- The <global> section is a fall through - they will only be used if the button is not -->
<!-- used in the current window's section. Note that there is only handling -->
<!-- for a single action per button at this stage. -->
<!-- For joystick/gamepad configuration under linux/win32, see below as it differs from xbox -->
<!-- gamepads. -->
<!-- The format is: -->
<!-- <device> -->
<!-- <button>action</button> -->
<!-- </device> -->
<!-- To map keys from other remotes using the RCA protocol, you may add <universalremote> blocks -->
<!-- In this case, the tags used are <obc#> where # is the original button code (OBC) of the key -->
<!-- You set it up by adding a <universalremote> block to the window or <global> section: -->
<!-- <universalremote> -->
<!-- <obc45>Stop</obc45> -->
<!-- </universalremote> -->
<!-- Note that the action can be a built-in function. -->
<!-- eg <B>XBMC.ActivateWindow(MyMusic)</B> -->
<!-- would automatically go to My Music on the press of the B button. -->
<!-- Joysticks / Gamepads: -->
<!-- See the sample PS3 controller configuration below for the format. -->
<!-- -->
<!-- Joystick Name: -->
<!-- Do 'cat /proc/bus/input/devices' or see your xbmc log file to find the names of -->
<!-- detected joysticks. The name used in the configuration should match the detected name. -->
<!-- -->
<!-- Button Ids: -->
<!-- 'id' is the button ID used by SDL. Joystick button ids of connected joysticks appear -->
<!-- in xbmc.log when they are pressed. Use your log to map custom buttons to actions. -->
<!-- -->
<!-- Axis Ids / Analog Controls -->
<!-- Coming soon. -->
<keymap>
<global>
<remote>
<skipminus>VolumeDown</skipminus>
<skipplus>VolumeUp</skipplus>
<pause>Info</pause>
<stop>stop</stop>
<play>NextLetter</play>
</remote>
</global>
<FullscreenVideo>
<remote>
<select>OSD</select>
<skipplus>VolumeUp</skipplus>
<skipminus>VolumeDown</skipminus>
<pause>Pause</pause>
<stop>Stop</stop>
<play>Play</play>
<up>NextSubtitle</up>
<down>Mute</down>
</remote>
</FullscreenVideo>
<Visualisation>
<remote>
<left>SkipPrevious</left>
<right>SkipNext</right>
<up>IncreaseRating</up>
<down>DecreaseRating</down>
<pause>Pause</pause>
<stop>Stop</stop>
<play>Play</play>
<select>XBMC.ActivateWindow(MusicOSD)</select>
<skipminus>Back</skipminus>
<skipplus>Info</skipplus>
</remote>
</Visualisation>
</keymap>
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