How to Add Federated engine after installing Mysql

I have Mysql 5.5.18 and upon show engines:

show engines;
+--------------------+---------+------------------------------------------------------------+--------------+------+------------+
| Engine             | Support | Comment                                                    | Transactions | XA   | Savepoints |
+--------------------+---------+------------------------------------------------------------+--------------+------+------------+
| InnoDB             | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES          | YES  | YES        |
| PERFORMANCE_SCHEMA | YES     | Performance Schema                                         | NO           | NO   | NO         |
| MRG_MYISAM         | YES     | Collection of identical MyISAM tables                      | NO           | NO   | NO         |
| CSV                | YES     | CSV storage engine                                         | NO           | NO   | NO         |
| MyISAM             | YES     | MyISAM storage engine                                      | NO           | NO   | NO         |
| MEMORY             | YES     | Hash based, stored in memory, useful for temporary tables  | NO           | NO   | NO         |
+--------------------+---------+------------------------------------------------------------+--------------+------+------------+

as you see federated engine is not one of the list. i need to enable it!! any idea of why BLACKHOLE, FEDERATED, and ARCHIVE engines are missing from the list? and how can i add/enable them? **EDIT** I have ubuntu 11.10 and installed mysql from ppa ... i have added the following to /etc/apt/sources.list

deb http://ppa.launchpad.net/nathan-renniewaldock/ppa/ubuntu  oneiric main
deb-src http://ppa.launchpad.net/nathan-renniewaldock/ppa/ubuntu  oneiric main

Thanks for your help