Hyun,
Try selecting the starting point on your bus and then move a short distance in the opposite direction that you wish to go, the move back in the intended direction. For example, if you wish to come off of a vertical bus, select the right wire as your starting point, move left, past the left wire, then move to the right to the point where you wish to stop. It's a similar process for coming off of a horizontal bus, just go up first, then down. You will probable have to experiment a bit with this, but it works very nicely.
Martin