Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: 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_CLEAR