Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Reset on Frame 0
FIELDLAYER_PYTHON_RESETFRAME0Parameter: FIELDLAYER_PYTHON_FRAME
FIELDLAYER_PYTHON_FRAMEParameter: Code
FIELDLAYER_PYTHON_CODEParameter: Open Python Editor
FIELDLAYER_PYTHON_OPENEDITOR