Use FM: CS_BOM_EXPL_MAT_V2
Pass the following parameters from MARA table of Material Variant:
CUOBJ = MARA-CUOBF
MTNRV = MARA-SATNR
If the material variant is active at plant level pass the following from MARC table of Material Variant:
CUOBJ = MARC-CUOBJ
MTNRV = MARC-STDPD
And the following also:
DATUV = today's date
EMENG = 1.00
MEHRS = X
WERKS = plant
See if it works.