The way I've done it is to make the elevator and name it with the coresponding animation tag. Then make a small box and place this on the elevator axis line with the axis alined. Change the properties of the box to make it a hierarchy node so it doesn't apper in the finished model and name it with the coresponding alieron tag "l_alier" or "r_alier" (these are stock animation names). Finally, make the Alieron a parent of the elevator (option found in elevators properties). Now when the alieron moves the elevator moves with it but if you also move the elevator you get an increaced or decreaced deflection depending on direction. You may want to adjust the angles of deflection to achive a realistic result. Using stock animation this is done by adjusting values in the AIR or CFG files.
Hope this helps.