It may be necessary for the Accounting Seed integration to use an alternate product when populating sales tax.
Assuming you have the product you want to use setup already:
- Go to the AvaTax Settings tab in Salesforce. This may require clicking on the '+' on the navigation bar to see all tabs.
- Go into the settings you are using (generally there is only one).
- Change the SalesTax Product Code entry to match the product code of the desired product.