Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Texture
MOSAICSHADER_TEXTUREParameter: Smooth
MOSAICSHADER_SMOOTHParameter: Tiles U
MOSAICSHADER_TILE_UParameter: Tiles V
MOSAICSHADER_TILE_V