Zach- At this time, the only way to add or update sales tax IDs is to add them manually in AR, Utilities, Sales Taxes, Maintain.  There is an enhancement to be able to import sales taxes, if you would like to follow the enhancement, here is the article "Enhancement Request: Globally change or import sales tax rates in Accounts Receivable" (80672).  If you would like to see this feature considered for a future release please send your request to [email protected].

Thanks,

Coleen