Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Freeze
FREEZE_FREEZEParameter: Variation
FREEZE_VARParameter: Over Age
FREEZE_OVERAGEParameter: Age Gradient
FREEZE_AGEGRADParameter: On
IN_FREEZE_ONParameter: Animation Time
IN_FREEZE_ATIME