Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Direction
EXTRUDEOBJECT_DIRECTIONParameter: Offset
EXTRUDEOBJECT_EXTRUSIONOFFSETParameter: Movement
EXTRUDEOBJECT_MOVEParameter: Subdivision
EXTRUDEOBJECT_SUBParameter: Isoparm Subdivision
EXTRUDEOBJECT_ISOPARMParameter: Reverse Normals
EXTRUDEOBJECT_FLIPNORMALSParameter: Hierarchical
EXTRUDEOBJECT_HIERARCHIC