Till what time is the Beijing airport shuttle bus?

we would be arriving at 12:05 midnight at the Beijing Capital Airport on june 6, 2011. we would be finished at the immigration and getting our luggages approximately 30-45 minutes. So that would be around 12:45am to 1:00am. we plan to ride the shuttle bus at line 2 to its terminal in Xedan. Can we still catch the shuttle bus at this hour? thanks for the help!