Draft Orders - Tax Exempt - Tax Not Being Deducted

[Max1957]

My site correctly shows tax free prices at checkout when the customer enters a delivery region that has been set up not to collect taxes.  That all seems to work fine.  HOWEVER, when I create a draft order for an existing customer in a tax free region, the Draft Order shows the product price including tax, even if I have flagged the customer as tax exempt.  Any help gratefully appreciated