Sage One integration is in the planning stage and will be available in the near future.
In the meantime, Tradebox One can still be used to download all of your online orders and quantify the VAT on every item based on what you sell and where you ship it. Sales data can be exported to CSV and imported into your accounts package directly. Or you can summarise your sales in Tradebox and manually enter these as batch invoices in your accounts package. Every order downloaded into Tradebox One can be passed into Sage One when the integration becomes available.