You can setup additional VAT rates in Accounting Settings >> Advanced Features:
The problem is separating out your Italian sales from your UK sales and outputting these to distinct reports. QuickFile does not support VAT accounting rules for Italy and can be used only to prepare and submit UK VAT returns.
You would need therefore to mark your Italian sales as out of scope for UK VAT, so they don't appear on the UK return. You would then need to manually calculate your Italian Sales (you could apply a project tag to isolate them) and from there to export and prepare the Italian VAT return.