For a Projects Supplier Invoice captured in AP we need the Tax line type to be the ETax Tax Rate non

We have customized projects supplier invoice account generator.Default Generate Account process according to PA Implementation Guide. In AP, we enter Supplier cost account against the project. No problem.This fires the PAAPINVW.wft . But PAAPINVW.wft derives the same GL account for the AP invoice line item and tax line types. We need Tax line type to be the ETax Tax Rate non recoverable tax distribution.

Must we customize projects supplier invoice account generator.Default Generate Account process to derive the tax GL distribution ?
But there is no lookup_type_code in PAAPINVW.wft to distinguish between the ITEM line type and the TAX line type ? PAAPINVW.wft returns a single GL account for the ITEM line type.