I have been successfuly by the following.
Using the tire wrench from the trunk (or from memory 3/4" socket?)
1. loosen the idle pulley nut (break free)
2. then wrench back on idle pulley nut and remove tension from belt.
3. put a metal spacer in the gap of tensioner that shows/measures tension
to hold tensioner off belt.
4. now wrench the idle pulley bolt off (rotating the other way and take
the nut out)
5. remove pulley, then remove old belt
6. install new belt, slide idle pulley under belt & on to shaft
7. reinstall idle pulley nut, put wrench on nut, & tension the tensioner to remove metal spacer.
8. retighten the idle pulley nut.
Inother words:
I have been successfuly by first removing the idlle pulley
(while maintaining belt tensioner in off mode),
then installing the SC belt in place, then sliding the idle pulley
under the belt and back on the post.
(this has to be coordinated with tensioner, I carefully put a metal bar
in tensioner gauge to maintain tension off the belt, while moving
the idle pulley on and off)