<?
$toto["001"]="a";
$toto["010"]="c";
$toto[(string)"100"]="d";
$toto["002"]="b";
$toto["110"]="e";
 
ksort($toto);
for(reset($toto); $test = key($toto); next($toto)) {
  echo ($test." (".gettype($test).") : ".$toto[$test]."<BR>\n");
};
?>

gives
100 (integer) : d<BR>
110 (integer) : e<BR>
001 (string) : a<BR>
002 (string) : b<BR>
010 (string) : c<BR>

instead of :
001 (whatever) : a<BR>
002 (whatever) : b<BR>
010 (whatever) : c<BR>
100 (whatever) : d<BR>
110 (whatever) : e<BR>

It is agreed that it is not a bug, but the intended functionality is still
not available.

To make it available at some later time, I would suggest putting either
kasort() or kusort() in some TODO list.
By kasort() I mean a variation of ksort() which only considers the
string value in the sorting comparisons. It wouldn't have to change the
types of keys inside the array, just sort them in another way.
By kusort() I mean to do something like:
function cmp($a,$b) {
  if($a==$b) return 0;
  return ((string)$a>(string)$b) ? 1:-1;
}
kusort($toto, cmp):


[config irrelevant]