Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Mode
FP_MESHEMITTER_MESH_MODE
Parameter: Voxel Size
FP_MESHEMITTER_MESH_VOXELSIZE
Parameter: Scatter
FP_MESHEMITTER_MESH_SCATTER
Parameter: Restriction
FP_MESHEMITTER_MESH_RESTRICTION
Parameter: Draw Geometry
FP_MESHEMITTER_DRAW_GEOMETRY