Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Texture
MOSAICSHADER_TEXTURE
Parameter: Smooth
MOSAICSHADER_SMOOTH
Parameter: Tiles U
MOSAICSHADER_TILE_U
Parameter: Tiles V
MOSAICSHADER_TILE_V