Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Cache Location
ID_VOLUMECACHELAYER_CACHE_MODEParameter: Path
ID_VOLUMECACHELAYER_FILEPATHParameter: Animation
ID_VOLUMECACHELAYER_ANIMATIONParameter: From
ID_VOLUMECACHELAYER_FROMParameter: To
ID_VOLUMECACHELAYER_TOParameter: Cache
ID_VOLUMECACHELAYER_BUTTON_CACHEParameter: Refresh
ID_VOLUMECACHELAYER_BUTTON_REFRESHParameter: Clear
ID_VOLUMECACHELAYER_BUTTON_CLEARParameter: Move Cache to Internal
ID_VOLUMECACHELAYER_CONVERT_TO_INTERNALParameter: Move Cache to External
ID_VOLUMECACHELAYER_CONVERT_TO_EXTERNAL