Ordinary characters such as 'a' and 'A' are easy to fake:
  'a'  => press a, release a
  'A'  => press shift, press a, release a, release shift

However @ is a bit more problematic (even though a latin character). For example on a swedish keyboard layout you'd do:
  '@'  => press alt-gr, press 2, release 2, release alt-gr
whereas on a german keyboard you'd do:
  '@'  => press alt-gr, press q, release q, release alt-gr
 
How to solve this and take into concern completely differant character sets....