1. Use everything from a mod folder only.
2. Copy the new edited RaceConfig.xml file with your values (no typos, not even a missing */* anywhere) straight into the root of the DATA folder. That file will replace the default.
3. Clear up your 'C:\Documents...' folder from whatever race files (well, at least those who ARE using the same Race number as your newly modded slots - that, if you'd want to keep your personal custom races & to make sure the opponents list is initialized properly).
4. Activate that mod. Exit right away. Re-load to start a fresh new game.
5. New names & descriptions should show up as intended (97%+ sure).
Although, i presume you are using a DarkAvatar game_setup. DL or TA should be no different unless for a few more specific items which are version dependant.