I make a screen for you, just for you, justttt for youuuu xD
Just google omg first link ^^
With some links:
You just have to check two cases, install and restart and vouala you can change chinese republic ...
Edit 1
For external connections, like Celestia, i think we must edit listener.ora on the same folder than TNSNAMES.ora
Edit 2
al3css, you managed to use the original client, but it's not working for some pple especially me lol ...