Hi Yuri!
I'm using postgresql 9.3, and I really had no problem in generating SQL.
I had some problems while migrating from my old server, to the new one, because I used the wrong version of the JDBC driver, but, after correct it, I don't have other problems.
Should you try to use another version? Just to check if there is a problem with the JDBC adaptor.
About integration with other apps, I should advice you use SEQUENCEs. They are useful, because they allow integration with direct queries.
As Check said, WO need to know the primaryKey for the EO created, so it needs to use sequences directly. If you look at the SQL code generated while insert a row, you will see:
SELECT NEXTVAL('TABLE_seq');
INSERT INTO TABLE (id, ....) VALUES (GENERATED_NUMBER, ...);
This is how WO generate next PK for EO in PostgreSQL.
In external Apps, if you don't need to know the PK, or doing works with SQL queries, you can do it directly:
INSERT INTO TABLE (id, ...) VALUES (NEXTVAL('TABLE_seq'), ....);
Using NEXTVAL() the sequence return the next pk and increment the internal counter.
Hope this helps you.
Best regards,
Daniele