Help with plan changing inner to left join problem ..

Hi

i have this plan

SELECT
H.*, A.DT
FROM
HIST_DB H
INNER JOIN ADRESY_DB A ON H.ID_OBJ=A.ID
PLAN JOIN (H ORDER IXA_HIST_DB__DATAP__CZASP, A INDEX (PK_ADRESY_DB__ID))
ROWS 1000
ORDER BY H.DATAP ASC, H.CZASP ASC


and if i change inner join to Left Join this plan can not by used why?
how can i optimize this query plan for Left Join

SELECT
H.*, A.DT
FROM
HIST_DB H
LEFT JOIN ADRESY_DB A ON H.ID_OBJ=A.ID
PLAN JOIN (H ORDER IXA_HIST_DB__DATAP__CZASP, A INDEX (PK_ADRESY_DB__ID)) /* 
error IXA_HIST_DB__DATAP__CZASP can not be used i specified plan */
ROWS 1000
ORDER BY H.DATAP ASC, H.CZASP ASC


please help
Karol Bieniaszewski