Did a little digging and came up with a parts breakdown of the entire booster. If you PM your email address or fax #, I'll get it over to you.
I just realized that you have a Duetto Jr. Pretty rare car! Fellow BB member Alex C. also has one and is quite knowledgable about it. I don't believe the cardisc cds cover the Jr. models. However, the 1600 and/or the 1750 cds may be very helpful. If you're a member of the
Alfa Romeo Owners Club , owners, parts and service manuals are available.