For non-USA versions of QuickBooks (CA, UK, etc.):
What you have should work, ASSUMING that the Sales Tax Code "SBT" is correctly mapped to a tax rate in your tax preferences within QuickBooks.
For USA versions of QuickBooks:
Sales tax codes just indicate whether something is TAXable, or NONtaxable. They do NOT actually indicate any tax amount, or force tax to be recorded/charged.
In addition to the Sales tax code, you also need to specify an ItemSalesTaxRef, which is a reference to a specific tax item (a specific tax rate, e.g. 7%).
...
<ItemSalesTaxRef>
<FullName>My Existing Tax Item Name</FullName>
</ItemSalesTaxRef>
<IsToBePrinted>true</IsToBePrinted>
...