Withholding Tax Visibility to Supplier

The client I am working with just recently setup Withholding tax.  They are using it at Invoice Validation time for both application and creation of the withholding invoice to the IRS.  One of the issues we are running into is that the payment does not have any details why the invoice amount is less the withholding rate.

Does anyone have a way they work around this to add this to the remit or to the check template for the suppliers taking this withholding?

Thanks,

Kevin