Index: wp-admin/includes/post.php
===================================================================
--- wp-admin/includes/post.php	(revision 17572)
+++ wp-admin/includes/post.php	(working copy)
@@ -1092,6 +1092,7 @@
 		$uri = untrailingslashit($uri);
 		$uri = strrev( stristr( strrev( $uri ), '/' ) );
 		$uri = untrailingslashit($uri);
+		$uri = apply_filters( 'editable_slug', $uri );
 		if ( !empty($uri) )
 			$uri .= '/';
 		$permalink = str_replace('%pagename%', "{$uri}%pagename%", $permalink);