Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Filename
SCENEINSTANCE_FILENAME
Parameter: Project Time
SCENEINSTANCE_STARTTIME
Parameter: Edit Project
SCENEINSTANCE_EDITSCENE
Parameter: Reload Project
SCENEINSTANCE_RELOADSCENE
Parameter: Take Animation
SCENEINSTANCE_ANIMATE
Parameter: Reload All
SCENEINSTANCE_RELOADALLSCENES
Parameter: Pivot Pos
SCENEINSTANCE_OBJECTS_PIVOT_POS
Parameter: Pivot Rotation
SCENEINSTANCE_OBJECTS_PIVOT_ROT
Parameter: Pivot Scale
SCENEINSTANCE_OBJECTS_PIVOT_SCL
Parameter: Pivot Matrix
SCENEINSTANCE_OBJECTS_PIVOT
Parameter: By Default
SCENEINSTANCE_OBJECTS_MODE