getUdateCount() vs. RETURNING clause

Hi,

I'm having a problem using an UPDATE statement with a RETURNING clause.

It seems I cannot retrieve the number of rows affected using getUpdateCount()

This is my statement

UPDATE my_table
  SET the_column = the_column + 1
  WHERE id = =
  RETURNING the_column;

My Java code is:

PreparedStatement pstmt = con.prepareStatement(UPDATE_SQL); // the statement from above
pstmt.setInt(1, 42);
boolean hasResult = pstmt.execute();

if (hasResult) {
  ResultSet rs = pstmt.getResultSet();
  if (rs != null && rs.next()) {
    int newId = rs.getInt(1);
    System.out.println("newid: " + newId);
  }
}

int affected = pstmt.getUpdateCount();
System.out.println("affected: " + affected);

I do see the returned ID from the ResultSet but getUpdateCount() always returns -1 even though I know that a row was
updated. 

What am I missing here?

My Postgres version is: 8.4.1
My driver version is: PostgreSQL 8.4 JDBC4 (build 701)
I'm using Java6 (1.6.0_16)

Regards
Thomas