Invoice doesn't support Postgresql

I enabled Invoice and saw a bunch of errors:

    * warning: pg_query() [function.pg-query]: Query failed: ERROR: syntax error at or near "precision_unsigned" LINE 6: vat double precision_unsigned NOT NULL default 0, ^ in /var/www/sites/project/includes/database.pgsql.inc on line 139.
    * user warning: query: CREATE TABLE invoice_items ( iid serial CHECK (iid >= 0), description text, quantity double precision NOT NULL default 0, unitcost double precision NOT NULL default 0, vat double precision_unsigned NOT NULL default 0, weight smallint_unsigned NOT NULL default 0, invoice_id int_unsigned NOT NULL default 0, uid int_unsigned, created timestamp without time zone NOT NULL, PRIMARY KEY (iid) ) in /var/www/sites/project/includes/database.inc on line 515.
    * warning: pg_query() [function.pg-query]: Query failed: ERROR: relation "invoice_items" does not exist in /var/www/sites/project/includes/database.pgsql.inc on line 139.
    * user warning: query: CREATE INDEX invoice_items_invoice_id_idx ON invoice_items (invoice_id) in /var/www/sites/project/includes/database.inc on line 515.
    * warning: pg_query() [function.pg-query]: Query failed: ERROR: relation "invoice_items" does not exist in /var/www/sites/project/includes/database.pgsql.inc on line 139.
    * user warning: query: CREATE INDEX invoice_items_uid_idx ON invoice_items (uid) in /var/www/sites/project/includes/database.inc on line 515.
    * warning: pg_query() [function.pg-query]: Query failed: ERROR: syntax error at or near "precision_unsigned" LINE 6: vat double precision_unsigned NOT NULL default 0, ^ in /var/www/sites/project/includes/database.pgsql.inc on line 139.
    * user warning: query: CREATE TABLE invoice_templates ( tid serial CHECK (tid >= 0), name varchar(100), locale varchar(25), date_format varchar(50), vat double precision_unsigned NOT NULL default 0, pay_limit smallint_unsigned NOT NULL default 0, supplier_company_name varchar(100), supplier_street varchar(100), supplier_building_number varchar(100), supplier_zipcode varchar(100), supplier_city varchar(100), supplier_country varchar(100), supplier_phone varchar(100), supplier_fax varchar(100), supplier_email varchar(100), supplier_web varchar(100), supplier_coc_number varchar(100), supplier_vat_number varchar(100), display_column_vat smallint_unsigned NOT NULL default 0, display_column_exunitcost smallint_unsigned NOT NULL default 1, display_column_incunitcost smallint_unsigned NOT NULL default 1, display_column_extotal smallint_unsigned NOT NULL default 1, display_column_inctotal smallint_unsigned NOT NULL default 1, PRIMARY KEY (tid), CONSTRAINT invoice_templates_name_key UNIQUE (name) ) in /var/www/sites/project/includes/database.inc on line 515.