Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Scene
FP_GROUP_SCENE_LINKParameter: Link to Default Scene
FP_GROUP_SCENE_LINK_TO_DEFAULTParameter: Draw Mode
FP_GROUP_DRAW_PARTICLES_MODEParameter: Draw Radius
FP_GROUP_DRAW_PARTICLES_RADIUSParameter: Size
FP_GROUP_DRAW_PARTICLES_SIZEParameter: Override Mode (Display)
FP_GROUP_COLOR_OVERRIDE_MODEParameter: Override Color (Display)
FP_GROUP_COLOR_OVERRIDE_CONSTANT