Does anyone know how we could populate box 4 on form 1099 with backup withholding?

There are a list of vendors that the A/P department has determined are subject to this. As a result, they have calculated the tax amount and added it as a deduction on the voucher distrib line and coded it to a non-employee backup W/H account. I have made adjustments on the Adjust Withholding page and ran the Post Withholding process, without any luck.

Thanks in advance.