Oracle outer join syntax (+): outer join not converted to inner

CREATE TABLE t1 (

  siteid varchar(25) NOT NULL default '',

  emp_id varchar(30) NOT NULL default '',

  rate_code varchar(10) default NULL,

  UNIQUE KEY site_emp (siteid,emp_id),

  KEY siteid (siteid)

) ENGINE=MyISAM;

INSERT INTO t1 VALUES ('rivercats','psmith','cust'), ('rivercats','KWalker','cust');

CREATE TABLE t2 (

  siteid varchar(25) NOT NULL default '',

  rate_code varchar(10) NOT NULL default '',

  base_rate float NOT NULL default '0',

  PRIMARY KEY  (siteid,rate_code),

  FULLTEXT KEY rate_code (rate_code)

) ENGINE=MyISAM;

INSERT INTO t2 VALUES ('rivercats','cust',20);

SELECT emp.rate_code, lr.base_rate FROM t1 AS emp 

LEFT JOIN t2 AS lr ON lr.siteid = emp.siteid WHERE lr.rate_code = emp.rate_code 

and emp.emp_id = 'psmith' AND lr.siteid = 'rivercats';

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

1	SIMPLE	lr	system	PRIMARY,rate_code	NULL	NULL	NULL	1	100.00	

1	SIMPLE	emp	const	site_emp,siteid	site_emp	224	const,const	1	100.00	

Warnings:

Note	1003	select 'cust' AS "rate_code",20 AS "base_rate" from "test"."t1" "emp" where 1

SELECT emp.rate_code, lr.base_rate FROM t1 AS emp, t2 AS lr

WHERE emp.siteid=lr.siteid(+) AND   lr.rate_code = emp.rate_code AND

emp.emp_id = 'psmith' AND lr.siteid = 'rivercats';

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

1	SIMPLE	emp	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where

1	SIMPLE	lr	ref	PRIMARY	PRIMARY	102	test.emp.siteid	1	100.00	Using where

Warnings:

Note	1003	select "test"."emp"."rate_code" AS "rate_code","test"."lr"."base_rate" AS "base_rate" from "test"."t1" "emp" left join "test"."t2" "lr" on("test"."lr"."siteid" = "test"."emp"."siteid") where "test"."lr"."rate_code" = "test"."emp"."rate_code" and "test"."emp"."emp_id" = 'psmith' and "test"."lr"."siteid" = 'rivercats'