Re: Here I go again
I have had experiences that are quite similar to what Heidi described. We have added a new cat to the family in a pretty regular pattern- when one cat turns 3 or 4, we've ended up getting another kitten. Each kitten wore down his "big brother" as we called it, until he would play. Rusty won over Elfie, Fella won over Rusty, and then Nito did his job of forcing his playing on a grumpy, but obliging Fella.
Another thing that I have found to help, is after the confinement stage, if the adult is still showing signs of dislike for the kitten, bring out some toys and play with the kitten within sight of the adult. I have notice that this often brings out "jealousy" or maybe just "inspiration" and I'll walk over to the adult and find that they are suddenly crazy about whatever toy they just saw kitten playing with. Playing in each other's company, even if it isn't with each other, seems to help enforce a truce between the cats. More often than not, they have become friends.
Of course, every cat is different, so do what feels right, and good luck!