Here is an interesting quote from J.J. Abrams over at IMDB. In the story Abrams claimed to have offered Shatner a cameo and Shatner turned him down. Again it seems that Shatner's story and Abrams story are quite different.
http://www.imdb.com/title/tt0060028/news#ni0767075
Abrams says, "His character died in one of the films and we wanted to be consistent.
"Everyone says - the Trek fans - if you're gonna do a Trek film, you need to be consistent. He died."
Abrams reiterates he did offer Shatner a role in his new film, but explained it could only be a cameo.
He adds, "It was clear that he didn't wanna just do a cameo, so to create a story which was in the movie, it would have been reworking everything (sic)."
But Abrams insists he didn't purposefully snub the original Kirk: "I love William Shatner"