I have tested his feature on my system using the following:
CREATE TABLE test_autoincrement (
id number(10) NOT NULL,
field1 varchar2(40) default NULL,
field2 varchar2(255) default NULL,
PRIMARY KEY (id)
);
CREATE SEQUENCE test_autoincrement_seq;
REVOKE ALL ON test_autoincrement FROM PUBLIC;
GRANT SELECT,INSERT,DELETE,UPDATE ON test_autoincrement TO PUBLIC;
REVOKE ALL ON test_autoincrement_seq FROM PUBLIC;
GRANT SELECT,ALTER ON test_autoincrement_seq TO PUBLIC;
I then imported this new table, imported the columns, after which I examined the ID column and noted that the autoincrement property was set correctly. When I exported the table details the dict.inc file showed 'auto_increment' => 'y' on the key field.
Are you sure that you are following the instructions at http://www.tonymarston.net/php-mysql/oracle.html#auto.increm ent