It's been my experience that commercial tools to seperate ball joints just don't work very well. Here's what I do(and it works every time(easily):
1. Wrap tin foil around the ball joint(except of course on the stud and end of the steering arm).This protects the rubber seal from the flame.
2. Heat the steering arm only with a propane torch. You don't need red-hot, only HOT. This should only take about a minute.
3. Get two hammers, one large(4lb) and one regular. place the large hammer against the backside of the steering arm and hold. Take the other hammer and strike the frontside of the steering arm. After two or three hits the balljoint should have popped out, especially if it's the tapered type.
The theory here is to expand the hole with heat. Hitting the steering arm deflects the metal enough to break the locking action of the taper. The backup hammer just allows more force to go into the steering arm instead of just bending it.
Good luck!