Help me to setup Thai keyboard on gnome!

[Paitoon Butri <paitoon grandlinux com>]

Hi all,
     I have problem in setup Thai keyboard on gnome. I installed Red Hat 7.3 
on my computers. While installing, I selected "English" (because of have no 
Thai).
    After installation, I try to install Thai fonts. It work ok. Then, I 
modified /etc/XF86Config and /etc/XF86Config-4 to set XkbLayout to "th".
   When I start X-windows,why can't I automatically swith keyboard to Thai 
(AltLeft + ShiftRight)? On gnome, I try to run "setxkbkmap th" command and 
switch keyboard to Thai again. The result, I can't input any charater. 

   Please, help me to fixed this problem.

   Thanks in advance.
   - Paitoon Butri