Post URL – changes

Hi,
I’m trying to make some changes and need your help with one.
Want automatically replace characters in post url from cyrillic to latin. I edit wp-includes/post.php but nothing happens. Then I edit wp-admin/includes/post.php but there is a function which only show permalink html.

Can u help me?

P.S: Here is the file wp-includes/post.php with my changes http://pastebin.com/fd585eaf