I would like to buy ticket SEA-YYZ-CPH-LED on Air Canada/SAS in economy class and return TLV-EWR-SEA on Continental in discount business class (Z).

I verified that Air Canada "S" fare SEA-LED and Continental Z fare TLV-SEA are perfectly combinable and called AC to book the ticket, since AC is the first transatlantic carrier.

It turned out that Air Canada does not see any discount CO fares in their system -- they can only book classes Y, B, D and A for CO flight, but not Z and not even any economy fare below B.

I would book my ticket on Expedia or Orbitz, but they do not allow combining economy outbound with business return.

Continental suggested a strange thing: buy economy roundtrip through Expedia, then call back CO and pay difference between whatever Y I got on the return and Z without any penalties, but it's a little scary. I think they did not realize that the ticket will belong to Air Canada and not sure how CO is going to modify it.

Any other suggestions? I am sure travel agent can do it manually, but calling a travel agent these days cost up to $100 extra + additional hassle if need to make any changes in the future.