c4d_base/description/obaselist.hParameters are accessed with cinema::C4DAtom::GetParameter() and cinema::C4DAtom::SetParameter(). See Parameters.
Parameter: Icon File / ID
ID_BASELIST_ICON_FILEParameter: Icon Color
ID_BASELIST_ICON_COLORIZE_MODEID_BASELIST_ICON_COLORIZE_MODE_NONEID_BASELIST_ICON_COLORIZE_MODE_CUSTOMParameter: Color
ID_BASELIST_ICON_COLORParameter: ID_BASELIST_ICON_PRESET_BUTTONS
ID_BASELIST_ICON_PRESET_BUTTONSParameter: Name
ID_BASELIST_NAMEParameter: Layer
ID_LAYER_LINK