[Newbie]key bindings

[newbie@XFree86.Org (Jon Bernard)]

Hello all,

  I've found all of the key binding def's I need for my keyboard in 
  /usr/X11R6/include/X11/XF68keysym.h. But xmodmap doesn't know about
  these keybindings and won't let me bind a keycode to XF86XK_Mail (for
  example). Is there a way to fix this, how can I use the keydefs in
  XF86keysym.h with xmodmap?

Thanks,

Jon