A simple multidimentional key aware array_diff function.
    
<?php    
function arr_diff($a1,$a2){
  foreach($a1 as $k=>$v){
    unset($dv);
    if(is_int($k)){
      // Compare values
      if(array_search($v,$a2)===false) $dv=$v;
      else if(is_array($v)) $dv=arr_diff($v,$a2[$k]);
      if($dv) $diff[]=$dv;
    }else{
      // Compare noninteger keys
      if(!$a2[$k]) $dv=$v;
      else if(is_array($v)) $dv=arr_diff($v,$a2[$k]);
      if($dv) $diff[$k]=$dv;
    }    
  }
  return $diff;
}
?>

This function meets my immidiate needs but I'm shure it can be improved.