Problem with a non apple keyboard on potato 2.2r0

[bda@free.fr]

i everybody

     I have some problems with my keyboard, i fixed some things with "xmodmap",
the 
     "q" button and the backspace.

     When i type "xmodmap -pk", i can see all the features beetween keycode and 
     keysim, with this i have fixed two of my three problems.

     I can't get a "@" with my keyboards, the button doesn't work.

     How can i affect this to another button ?

     My keyboard is not an Apple.

     Thanks 
     Dabowl