It's not like it's hard...
Code:
;Syntax: /loadchars <dialog name> <dialog ID>
alias loadchars {
  if ($2) {
   var %i = 1
   while (%i <= 255) { .did -a $1 $2 $chr(%i) | inc %i }
  }
  else { did -a $1 $2 Error }
}