AvaTax 15 API does not support itemized discounting the way Magento does.
State Sales Tax Registration. Get registered. Popular Integrations. Magento
Solution: You'll need to install the PHP SoapClient library, per the prerequisites section.
Also see SOAP Error Codes for error messages defined in the SOAP v1 API.
How do I use Alabama's Simplified Seller Use Tax Remittance Act? How Do I Use a Freight Forwarder with Avalara
http://www.magentocommerce.com/magento-connect/sales-tax-extension-for- avalara-s-avatax.html. You can set table rates in Magento but there is not "Public" API for taxes available.
How Can I Export Magento Avatax Extension Error Logs?
Although Avalara is not an accounting solution in its traditional sense, we cannot pass it by.
API solutions for end-to-end tax compliance.
CYBERSOURCE DOES NOT PROVIDE TAX CONSULTATION SERVICES,