Wallace,
I had the same situation when replacing all of my belts last spring. The solution, after confirring with my Mercedes mechanic, was to cut the old belt off. You would then place the new belt on the crank pulley then on the top of the power steering pulley as far as you can then place a 27mm 1/2" drive short socket on the crank pulley with a 3" extension and a 1/2" drive ratchet. Turn the ratchet clockwise (when looking at the front of the engine) until the belt mounts the power steering pulley. If you feel you need to have a spare belt just buy another one.
Regards,
280SE Guy