Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Vertex Map
SLA_DIRTY_VMAP_OBJECTParameter: Invert
SLA_DIRTY_VMAP_INVERTParameter: Color Space
SLA_DIRTY_VMAP_OCIO_COLORSPACE