I'm going to have to respectfully disagree with you on this one, Martin. I don't think Totti is all that pissed.
A couple thoughts about this deal:
1) Real Madrid has no clue as to what they just bitten off in recruiting Cassano. A person with his capabilities, that kind of self-image, and a tendency for throwing great tantrums risks being more of a liability than an asset to Real. Put him on the bench as much as Owen, and they'll end up trading him away within a year.
It is possible that Cassano, once away from the bad influence of Totti's captaincy, might mature more as a team player. But I don't expect it at a club where there's little discipline coming from the coaching staff down to the ego-centric players that litter their roster. The inmates run the asylum at Real Madrid.
Totti must know some of this.
2) Totti has made it rather evident that he'd prefer to be a big fish in the small pond of AS Roma than to strike out on his own at a bigger club elsewhere. Totti is a god in Rome, as a Roman, who arguably rivals if not exceeds the status of the Pope there. If Totti really wanted to prove himself in the world's top clubs, I think he would be there by now. Instead, I think he's comfortable staying in his provincial nest in Roma.
Totti probably has a bit of jealousy and envy over choices he's had that he has decided not to pursue, and Cassano reminds him of that. But he's made the bed he sleeps in. And he's there by choice.