expand_fast_index_creation is Broken For RENAME INDEX

This page http://www.percona.com/doc/percona-server/5.1/management/innodb_fast_index_renaming.html indicates that an extended RENAME INDEX clause is available, however after making sure fast_index_creation and expand_fast_index_creation is ON the it would return an invalid syntax error.

This has been tested on 5.5.28-29.2, 5.1.66, 5.1.59 (wiki says expand_fast_index_creation was implemented here), 5.1.56 (http://www.mysqlperformanceblog.com/2011/11/06/improved-innodb-fast-index-creation/ says expand_fast_index_creation was available since 5.1.56).

How to repeat:

mysql [localhost] {msandbox} (test) > CREATE TABLE `t` (
    -> `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
    -> `c` char(1) DEFAULT NULL,
    -> PRIMARY KEY (`id`),
    -> KEY `cxc` (`c`)
    -> ) ENGINE=InnoDB DEFAULT CHARSET=latin1;
Query OK, 0 rows affected (0.11 sec)

mysql [localhost] {msandbox} (test) > show variables like '%fast_index_creation';
+----------------------------+-------+
| Variable_name | Value |
+----------------------------+-------+
| expand_fast_index_creation | OFF |
| fast_index_creation | ON |
+----------------------------+-------+
2 rows in set (0.00 sec)

mysql [localhost] {msandbox} (test) > set expand_fast_index_creation=ON;
Query OK, 0 rows affected (0.00 sec)

mysql [localhost] {msandbox} (test) > show variables like '%fast_index_creation';
+----------------------------+-------+
| Variable_name | Value |
+----------------------------+-------+
| expand_fast_index_creation | ON |
| fast_index_creation | ON |
+----------------------------+-------+
2 rows in set (0.00 sec)

mysql [localhost] {msandbox} (test) > alter table t rename index cxc to cxx;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'index cxc to cxx' at line 1