Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Animation
VDBIMPORT_ANIMATIONParameter: From
VDBIMPORT_FRAME_STARTParameter: To
VDBIMPORT_FRAME_ENDParameter: Group Objects
VDBIMPORT_GROUP_OBJECTSParameter: Import to Project Location
VDBIMPORT_RELATIVE