Hi Elena,
Sorry for the delay in responding to this post. I can confirm that the option to select VAT treatment to use goods/services from UK supplier is used for UK businesses to account for VAT from other UK entities.
What you are requesting for, would be a feature request where a Maltese or other non UK based company can select a VAT treatment to incorporate the locat VAT rate on goods/ services from Malta or other non UK location.
However, there is an option for you to set the manual vat rate on invoices and bills, which you might find of certain benefit.
Please let me know if there is anything else I can do to assist you?
All the best,
Shaz