Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Random Seed
ST_SEED
Parameter: Type
ST_TYPE
Parameter: Birth Type
ST_BTYPE
Parameter: Count
ST_COUNT
Parameter: Rate
ST_RATE
Parameter: Shot
ST_SHOT
Parameter: Life
ST_LIFE
Parameter: Life Variation
ST_LIFEVAR
Parameter: Speed
ST_SPEED
Parameter: Speed Variation
ST_SPEEDVAR
Parameter: Size
ST_SIZE
Parameter: Size Variation
ST_SIZEVAR
Parameter: X Fov
ST_XANGLE
Parameter: Y Fov
ST_YANGLE
Parameter: X Size
ST_XSIZE
Parameter: Y Size
ST_YSIZE
Parameter: Distance
ST_DIST
Parameter: Distance Variation
ST_DISTVAR
Parameter: Spin
ST_SPIN
Parameter: Spin Variation
ST_SPINVAR
Parameter: Spin Type
ST_SPINTYPE
Parameter: Spin Axis
ST_SPINAXIS
Parameter: On
IN_ST_ON
Parameter: Animation Time
IN_ST_ATIME
Parameter: Emitter Alignment
IN_ST_ALIGNMENT
Parameter: Emitter Velocity
IN_ST_VELOCITY
Parameter: Emitter Position
IN_ST_POSITION
Parameter: Birth Count
OUT_ST_PARTICLECOUNT
Parameter: Birth Num
OUT_ST_PARTICLENUM