I'm not sure if this is quite the same, but I experimented and found that I could get YVR-YYZ-MXP (Nov. 11/12), MXP-MUC-MAD (Nov. 13), MAD-FRA-YVR (Nov. 17) - booked via FlightHub and coded as Lufthansa for $670 USD ($842 CAD). Adding SEA didn't seem to help anything.
Similarly - YVR-YUL-BRU (Nov 11/12), BRU-MAD (Nov. 13), MAD-FRA-YVR (Nov. 17), coded on Air Canada, Brussels, and Lufthansa for $640 USD ($805 CAD).