I want to add witholding tax Code in BAPI_ACC_DOCUMENT_POST for tcode F-48

I want to add Witholding tax code in BAPI_ACC_DOCUMENT_POST for standard tcode F-48.

Requirement : Witholding tax should be calculated on G/L Account Total Amount (Including tax) not on Vendor.

For example.

If total Amount is Rs 11,800 then witholding tax amount should be 11,800 * 2.00% = 236

then when we enter Document Number in FB03 Tcode

then Entry should look like

G/L Amount -11564

Vendor Base Amount 10000

Tax Amount1 9% 900

Tax Amount2 9% 900

Witholding Tax Amount -236

then how to write it in Program. Thank You in Advance