I agree :nod: Edmund is my favourite character, and that scene was one of the best from him!!!
No, in the books Caspian and Susan met until the end, so nothing happened between them, actually I think they don't even share any lines :look:
It's something completely new for the movie
Spoilers ahead, just read it if you're really interested to know, if not, better read the books by yourself, they're amazing stories, this is just a barely idea...
[sp]In the final book "The last battle", Peter, Edmund, Lucy and others return to Narnia to help, except Susan, because she's no more a "friend of Narnia", she's now more interested in lipsticks, parties and guys. You can say she lost her faith on Narnia. So the controversy has always been if at some point Susan reacts, and if she's able to get back once again. C.S. Lewis wrote another book talking about Susan, I think :look: [/sp]