Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Mode
FP_MESHEMITTER_MESH_MODEParameter: Voxel Size
FP_MESHEMITTER_MESH_VOXELSIZEParameter: Scatter
FP_MESHEMITTER_MESH_SCATTERParameter: Restriction
FP_MESHEMITTER_MESH_RESTRICTIONParameter: Draw Geometry
FP_MESHEMITTER_DRAW_GEOMETRY