Even in winblows, AltGr 7 and AltGr 0 should work. Keyboard layouts 141 and 142 are standartised and both of them have '{' and '}' at these positions. If they haven't on your comp then it is a problem of the keyboard driver. Also try Shift AltGr é and Shift AltGr +, this is a Linux keyboard. The simplest solution should be the keyboard switcher. It is (it should be) a part of the operating system, even in winblows, and it should be already installed but not activated.
Select a keyboard switch key (for example, Ctrl-Shift) and install US keyboard along with the Italian one. When you are going to program, switch to US keyboard and you will have the brackets at Shift é and Shift +. When you have finished programming, switch to the Italian keyboard. You can switch the keyboard even during entering a text so that you can comment in Italian if you want.