I use two 10" shutter release cables. I screw one on the lens, and one into the shutter release button. Just as Kevin said, you depress the shutter release button on the camera body, that triggers mirror up. Then trigger the actual shutter on the lens. There's a section in the manual that covers it, if that helps.

http://www2.webster.edu/acadaffairs/...20PRO%20II.pdf