sequence behavior - is this correct

Hello,
I would like to ask if my problem with sequence is a proper behavior or
this is a bug (probably not)...

I have a table:

CREATE TABLE "testtable" (
"serialfield" SERIAL,
"someotherfield" TEXT,
PRIMARY KEY("serialfield")
) WITH OIDS;

After creation of this table, sequence "testtable_serialfield_seq" is
automatically created, with start value set to "1".

CREATE SEQUENCE "public"."testtable_serialfield_seq"
INCREMENT 1 MINVALUE 1
MAXVALUE 9223372036854775807 START 1
CACHE 1;

And now I have to insert into this table some records from other rdbms
(like MySQL) using sql inserts generated by e.g. mysqldump - it is a
simple import of data, where "serialfield" has got some value...

INSERT INTO testtable VALUES (1, 'sdsdsd');
INSERT INTO testtable VALUES (5, 'sdsdsd');
INSERT INTO testtable VALUES (10, 'sdsdsd');

And my question is: how sequence should react for this ? Right now start
value of the sequence is still "1", so if I will make a query like
"INSERT INTO testtable (someotherfield) VALUES ('sdsdsd')" then new
record's serialfield will have value set to "1" - of course this record
will not be created, because of primary key - but next insert will
create a new record with serialfield set to "2".

I didn't notice this problem before, because I have never made any
imports of data in this way..

Window/Cygwin
PostgreSQL 8.0.0beta3

Regards,
ML