The only buttons available for posting or unposting multiple Billings are the standard Accounting Seed buttons. To quickly post many billings with tax, the AvaTax version of these buttons is necessary.
- In Salesforce, go to the Setup section.
- Under App Setup (on the left panel) go to Create->Objects.
- Click on the Billing object.
- Under the Search Layouts, modify the layout that you use when multi-posting.
- Swap out the normal posting options for the new AvaTax ones and save.