Like the previous GTA games, the import/export job is included. In San Andreas, you do not get the chance to do any exporting or importing until you complete the mission 'Customs Fast Track'. Customs fast track is one of CJ's garage missions, which only becomes available when you buy Wang Cars (opposite the building site next to CJ's garage). Wang car's can only be bought when you get at least bronze for all test in driving school and completing the mission "Ya Ka Boom Boom". Find out more from the Getting wang cars topic.
Once this mission is complete, you can return to the docks to find a blackboard with a list of cars on it. There is also the yellow crane next to the ship that you used in the mission.
Basically all you have to do is find the vehicle's located on the list's. There is 3 lists in total, each one must be completed before you move onto the next.
