Have a look back at the thread created not long ago re rust to brakes. Link below:
http://ducati1199.com/ducati-1199/3897-rust-front-rotors-but-what.html
Go to the second page and I've posted up some photos of where my front rotors were rusting. Hope that helps.
Ok - saw the pictures, looks like you got lucky and they gave you a new rotor under warranty!
I will have a look and see if mine is doing the same.
Another thing you could have a look for is leaks with in the exhaust pipe especially where there is a connection with the springs close to the outlets, I think mine leaks there and I can see smoke coming out from that region when the bike is cold and smokes. This is something I was going to speak to the dealer about.