Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Filename
SCENEINSTANCE_FILENAMEParameter: Project Time
SCENEINSTANCE_STARTTIMEParameter: Edit Project
SCENEINSTANCE_EDITSCENEParameter: Reload Project
SCENEINSTANCE_RELOADSCENEParameter: Take Animation
SCENEINSTANCE_ANIMATEParameter: Reload All
SCENEINSTANCE_RELOADALLSCENESParameter: Pivot Pos
SCENEINSTANCE_OBJECTS_PIVOT_POSParameter: Pivot Rotation
SCENEINSTANCE_OBJECTS_PIVOT_ROTParameter: Pivot Scale
SCENEINSTANCE_OBJECTS_PIVOT_SCLParameter: Pivot Matrix
SCENEINSTANCE_OBJECTS_PIVOTParameter: By Default
SCENEINSTANCE_OBJECTS_MODE