When you say ball ends, are you talking about the ball socket attached to the end of the shifter cable or the ball studs on the transmission's shifter arms?
If you pull the clips, the socket pops off the ball with a twisting action. If it's not coming off you probably didn't remove the clip. Likewise, that clip must be removed from the one in the kit to put it on. Don't forget to reinstall the clip to make sure the socket doesn't pop off the ball during use.
I'm confused as to why a vice would be needed. If anything, you might need needle nose pliers to get the clips to rotate but they are generally pretty easy to remove.