1. Make sure you have the latest version of Desktop Manager installed. It's 4.3, download from http://na.blackberry.com/eng/services/desktop/req_4dot3.jsp 2. Download the above file to the PC then install it to the PC by running the file you downloaded. (Choose the Curve 8310) 3. Locate the vendor.xml file and delete it. It's located in c:\program files\common files esearch in motion\apploader 4. Plug in BB and Open Desktop Manager. You should be prompted to upgrade.
Have some patience, this could take an hour to complete. DO NOT unplug the device until it is finished!
I also wanted to mention to everyone that just because this OS is from TIM Italy, doesn't mean you will suddenly have an Italian Blackberry. All you have to do is NOT select a language on the install and it will automatically install the OS in English. Also, like Tragedy said, dont forget to delete the vendor.xml file or else it wont load. Happy Berrying!!!