Trying to insert an array using a prepared statement.

I'm trying to insert an array into an array column, with no great success.
Has anybody gotten this to work, and if so, may I inquire how?

I've tried using both text and binary arguments as described below. I'm
using Postgresql 8.2.4 with the jdbc driver postgresql-8.3.604.jdbc4.jar on
a Linux box.

Text attempts.

java.sql.PreparedStatement st = conn.prepareStatement("insert into
vectortest(a) values(?)");
st.setString(1, "{1,2,3}");
st.execute();

which threw the exception:
org.postgresql.util.PSQLException: ERROR: column "a" is of type integer[]
but expression is of type character varying

java.sql.PreparedStatement st = conn.prepareStatement("insert
into vectortest(a) values(?::integer[])");
st.setString(1, "{1,2,3}");
st.execute();

which threw the exception:
org.postgresql.util.PSQLException: ERROR: cannot cast type character varying
to integer[]

Binary attempt:
I first queried a table containing an integer [] column to determine that
the the baseTypeName was int4 and that the array was passed in the form of
an array of java.lang.Integer objects.
I implemented the java.sql.Array interface (ignoring the map arguments in
the getArray methods), and tried the below sequence of statements.

java.sql.PreparedStatement st = conn.prepareStatement("insert
into vectortest(a) values(?)");
Integer []vals = new Integer[3];
vals[0] = new Integer(1);
vals[1] = new Integer(2);
vals[2] = new Integer(3);
st.setArray(1, new LinearArray(vals));
st.execute();

which threw the exception
org.postgresql.util.PSQLException: ERROR: array value must start with "{" or
dimension information

Any ideas appreciated.
Thank you.