I had the same reaction to the 350# number in the manual.
My problem was that this wasn't possible for me to accomplish.
In one of my many panic calls to Gary Hall, as I recall, he suggested that first you need the correct axle socket, and then go to sears and get the longest breaker bar that they have.
Take the whole mess and set it up to where you can stand on the bar (this one is up to the individual to figure out how) and just make the nut as tight as you can with your weight on the bar.
I think that will come out to roughly 350ft-lbs, depending on you weight and the length of the bar. That doesn't matter that much though. The point is "as tight as you can get it".
Don't come bitchin' back in the future that you can't get the frikin' thing loose...gain some weight and jump up and down on the bar.
Incidentally I may be mistaken but I think that number is well past the capacity of my impact wrench.