there is NO device that will do what you require.
the Xantech product does not 'convert' the 232 codes to IR, it simply responds to Xantech 232 codes and spits out whatever IR codes you have assigned to it.
your best route is to find out the discrete IR codes themselves, do you have any Hex codes that you can post that actually work for your TV which i believe is an LG?
Alternatively have you looked in the files section of this forum?
i also know you are using a Harmony so testing of these codes will not be an immediate process, let's start the ball rolling.....