If you have someone to help hold the pulley, then SEG's method is the easiest. However, if the pulley slips and you lose the spring tension, it shouldn't be a big deal. Look for a notch on the edge of the pulley. Once the end of the rope is secured to the pulley, you can pull the rope out through that notch. That way you can spin the pulley to put tension on the spring without wrapping the rope around the pulley. Once theres enough tension you line the notch up with the rope exit to pull the rope out of the notch and then you can let the spring pull the rope back in.
It should make sense if you look at your recoil.