At the very base of the shifter, right where it enters the tranny, you have to push down on that dome, and rotate it a little less and a 1/4 turn counterclockwise. It should then pop upwards a little bit and the shifter should come right out. I believe it is important to be in neutral as well. On some Cruisers I've been able to push it down and rotate it with my fingers, others are a little more stiff and then I just use the end of a big wrench or channel locks to push it down and rotate it. It stumped me the first time too. Heck...it probably stumped me the second time as well.
It's not really an issue of 'grabbing it'. Once you push it down, you just have to have enough fricton and force to actually turn it. The channel locks or the wrench are simply the right shape to be able to push down and still maintain force on it while turning it. I'm trying to think of a better way to describe it, but does that make sense?