Need advice or answers for airplane tickets!

[genesis0403]

Hi I always took direct flights or used travel agencies to book my tickets for me so I am not sure how the transfer system works when you buy tickets off from agencies or site such as expedia. I'm going to asia this month and I need to transfer once to get there. If i find a flight which I cannot find anywhere on expedia or travelocity, how can i get these to work as direct transfer flights?
What I am currently looking at is flying to San Francisco through Westjet making a stop at Vancouver, then flying over to Korea by Asiana Airlines. When I return, I fly to San Francisco by Asiana Airlines and fly directly to San Francisco but i can't seem to find any westjet transfered flights on any sights.... So how does this transfer system work when agencies book these tickets, and also if i contact the travel agency with exact flight details, can they make it to direct transfers? Thanks in advance

[GP_Matt]

A travel agent like Flight Centre should be able to make it work for you.

Otherwise, I have had luck just showing up at the airport to check in for the first leg and asking them to check my bags through to the end. (This is easier to accomplish in Canada than Asia on your return flight. Either way though you will have to collect your bags to clear Canadian customs at your first landing.

[Ryan Coke]

Unless the airlines involved have an interline agreement, you won't get your bags tagged between airlines. In this case you would clear US customs in Canada, pick up your bags in SFO, check in with Asiana there. On the way back, you would have to clear US customs in SFO, then go and checkin for Westjet, then clear Canadian customs once you get to Canada. I don't know off hand what terminal Asiana uses in SFO, so you'll have to check into that and how much time you will need to make the connection.

[genesis0403]

alright. thanks guys. the price difference was like $300 from what i saw on expedia and what i found so i had to find out how it works!