Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Animation
ID_CTRACK_ANIMOFFParameter: Solo Animation
ID_CTRACK_ANIMSOLOParameter: Constant Velocity
ID_CTRACK_CONSTANTVELOCITY_VParameter: Before
ID_CTRACK_BEFOREParameter: Repetitions
ID_CTRACK_BEFORE_CNTParameter: After
ID_CTRACK_AFTERParameter: Repetitions
ID_CTRACK_AFTER_CNTParameter: Loop End
ID_CTRACK_TIME_LOOP_ENDParameter: Time Track
ID_CTRACK_TIMEParameter: Relative Mapping
ID_CTRACK_TIME_RELATIVEParameter: Color from Preferences
ID_CTRACK_USE_PREFParameter: Color
ID_CTRACK_FCURVE_COLORParameter: F-Curve Offset
ID_CTRACK_FCURVE_OFFSETParameter: F-Curve Scale
ID_CTRACK_FCURVE_SCALEParameter: R23 Evaluation
ID_CTRACK_EVALUATION_MODE