That's not exactly how it went. If I recall correctly, Disney/Marvel and Norton came to some kind of agreement where Norton was hired as actor and writer. The only reason Norton became 'pissy' during the production was because of the lead writer Zak Penn getting sole writing credits, even though Norton had made some serious changes to the plot (again, as was discussed in his contract).
The 'bad blood' between Norton and Disney/Marvel came to be when they started the casting for The Avengers and decided that they didn't want Ed Norton to come back without letting Norton know of this decision. So when the word came out that they were looking for a new actor for Bruce Banner, while Ed Norton had stated that he would love to come back, of course Norton was more than a little upset.