AutoEntry has a special option to enable Flat Rate Tax for FuseMetrix.
This option is only available when you have connected a workflow to FuseMetrix.
Connect your workflow to FuseMetrix
On the menu at the top, click on Settings
Click on Workflows
Find the workflow you want to enable Flat Rate Tax for, then click on the Edit button beside it
Check the box Flat Rate Tax
Any workflows that have Flat Rate Tax enabled, will automatically post the Total into FuseMetrix as Net, the VAT will be 0.00 and the VAT code will be T0.
You can override this default behavior by choosing a Tax Code manually.