HELP - How do I get this update to use an INDEX RANGED SCAN

[RJSHA1]

Hi,
The update beow uses an Index, I would like to know if there is anyway to make it do RANGE SCAN using the Index ???

UPDATE /*+ INDEX (WRK_STAGING_GL_POSTING WRK_STAGING_GL_POSTING_IK1) */ OST.WRK_STAGING_GL_POSTING
SET AMOUNT = AMOUNT + vAMOUNT,
LOCAL_CCY_AMOUNT = LOCAL_CCY_AMOUNT + vLOCAL_CCY_AMOUNT
WHERE EBE_PROCESS_ID = v_ProcessId AND
ACCOUNT_ID = vACCOUNT_ID AND
ACCOUNT_CCY_ID = vACCOUNT_CCY_ID AND
ACCOUNT_TYPE = vACCOUNT_TYPE AND
COB_DATE = vCOB_DATE AND
CURRENCY_TYPE_FLAG = vCURRENCY_TYPE_FLAG AND
GL_SUB_ACCOUNT = vGL_SUB_ACCOUNT AND
GL_SUB_BRANCH = vGL_SUB_BRANCH AND
LEGAL_ENTITY_ID = vLEGAL_ENTITY_ID AND
LOCAL_CCY_ID = vLOCAL_CCY_ID AND
REFERENCE = vREFERENCE AND
REVERSAL_TYPE = vREVERSAL_TYPE AND
SUB_STRATEGY_ID = vSUB_STRATEGY_ID AND
TRANS_CCY_ID = vTRANS_CCY_ID AND
BATCH_TYPE = vBATCH_TYPE AND
SOURCE_SYSTEM_ID = vSOURCE_SYSTEM_ID AND
MM_PL_IND = vMM_PL_IND;


The three columns EBE_PROCESS_ID
ACCOUNT_ID
ACCOUNT_CCY_ID
make up the index. Any help wpuld be appreciated.