Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Key Time
ID_CKEY_TIMEParameter: Lock Time
ID_CKEY_LOCK_TParameter: Breakdown Color
ID_CKEY_BREAKDOWNCOLORParameter: Interpolation
ID_DKEY_INTERParameter: Mute
ID_CKEY_MUTEParameter: Breakdown
ID_CKEY_BREAKDOWN