Reports & Discoverer :: WITH Clause In Report Builder

I'm trying to have RB use the following query:

WITH MY_DATASET
AS (SELECT /*+ materialize */
DISTINCT
N.NAME_ID NID,
NVL (TO_CHAR (RN.CONFIRMATION_NO), 'ACCOMPAGNATORE') CONF,
RN.RESV_NAME_ID,
MEV.TAX1_NO PARTITA_IVA,
[code]....

But although perfectly working in SQLDeveloper, RB returns an ORA-942 table does not exist error, pointing at MY_DATASET as the offending name.