Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Random Seed
OP_BORN_SEED
Parameter: Birth Type
OP_BORN_BTYPE
Parameter: Count
OP_BORN_COUNT
Parameter: Rate
OP_BORN_RATE
Parameter: Shot
OP_BORN_SHOT
Parameter: Life
OP_BORN_LIFE
Parameter: Life Variation
OP_BORN_LIFEVAR
Parameter: On
OP_BORN_IN_ON
Parameter: Animation Time
OP_BORN_IN_ATIME
Parameter: Birth Count
OP_BORN_OUT_PARTICLECOUNT
Parameter: Birth Num
OP_BORN_OUT_PARTICLENUM