I had no problem last year getting to MXP on a revenue ticket via FRA on LH (AC codeshare on the Atlantic portion) for around $900 all in RT. The other traveler on an Aeroplan routing was via ZRH on the return but we left MXP and arrived YYZ at the same time. If you are going to travel by train in Italy, then if you're going to Milan don't go to MXP - Malpensa is very far out of town and the train to the airport is not part of Trenitalia (use the bus instead to Centrale Stazione). You are better off going to Linate, which is close to town and connected to the Trenitalia system.