The bus to Milano Centrale departs every half hour from Malpensa. Journey time is 50 minutes. Even with a slight delay in arrival time, and time to get baggage and go through customs, you should make the 11:05 in time. There is also a train that runs from Malpensa, but I've never done this. Did you check their website?
http://www.airwise.com/airports/europe/MXP

Buon viaggio!

[This message has been edited by Nanook (edited 08-06-2000).]