Dear Talia,

I hope it's still possible to get response from this thread. 
My case: I sell on shopify where I charge customers in USD. I have quickbooks online Essential plan, multi-currency enabled, I have a VAT registered UK company. 
My customers pay me in USD, and I want to make an invoice in USD in which VAT requirements ( net amount, VAT amount) is displayed in the VAT summary in GBP. Now, I've done what you've written above, but on the VAT summary, it still uses USD.  I've talked with quickbooks support on 2 occasions, both of them said the on the invoice there can be only 1 currency displayed....
I am wondering now what is the truth and will I even be able to solve this problem.
Can quickbooks handle this? I don't have many experience in accounting software, but I think it should be a basic feature ( a smaller firm's software called freeagent handle's this without any problem).
Thanks in advance

Joe