Best way to track building going in and out of frame

Im running mocha V2 with AE CS5. Im tracking a building to later add a sign to it in after effects. However the footage pans back and forth from the person behind me and the building. So essentially, there is constant 180 degree turns. Mocha cant track the building when it leaves completely off frame as it gives me the warning diologue. What is the best way to track the building in this case?

Im running mocha V2 with AE CS5. Im tracking a building to later add a sign to it in after effects. However the footage pans back and forth from the person behind me and the building. So essentially, there is constant 180 degree turns. Mocha cant track the building when it leaves completely off frame as it gives me the warning diologue. What is the best way to track the building in this case?