It looks like (in alfred's pic ) that you are supposed to make a deeper groove in the ball groove so the tool will get a better grip?
Do you have a Dremel tool? One of those with a fiberglass reinforced cut-off wheel would work nicely for that operation.

And you use the torch on the outside of the case, keeping away from the bearing race...you don't want to heat that directly.
"Paint" the heat on...waving the torch back and forth, and all around the case to heat it quickly and evenly. Usually a little smoke will start to wisp out of the nooks and crannies...that's when it's good 'n hot...don't go much hotter than that. You don't need more than about a 2" long flame either...no need to really blast it.