Clearing Sales Tax at Header Level in an Order

Question

Hi,
I have a requirement to not charge any tax on an order if the credit card used on the order is a government credit card. Currently I have implemented this logic in USEREXIT_SAVE_DOCUMENT_PREPARE. I am able to clear out the sales tax at the line level but this change does not reflect at the header level. I have to manually click on update pricing to zero out the tax displayed at the header level. I could not find a variable to tap into header level pricing condition and tax value field.
I would greatly appreciate if any one can give me some pointers on where to look for header level data for tax. Also, is there any better user exit to implement this functionality.
Folliwing is the code I am using to clear out line item level tax:
          LOOP AT XKOMV INTO WA_XKOMV WHERE KSCHL EQ 'UTXJ'.    "GET THE TAX CONDITION
              CLEAR WA_XKOMV-KWERT.                               "Set the TAX to 0
              CLEAR WA_XKOMV-KAWRT.
              CLEAR WA_XKOMV-KBETR.
              MODIFY TABLE XKOMV FROM WA_XKOMV
                TRANSPORTING KWERT KAWRT KBETR.
          ENDLOOP.
          LOOP AT XVBAP INTO WA_XVBAP.    "GET THE TAX VALUE
              CLEAR WA_XVBAP-MWSBP.                               "Set the TAX to 0
              MODIFY TABLE XVBAP FROM WA_XVBAP
                TRANSPORTING MWSBP.
          ENDLOOP.
Thanks,
Paresh

Answer 1

Hi,
In the case of sales cycle, All the item level taxes are summirised and come to the header level. So we can't find the conditions at header level for taxes. Check the user exit , because, the values are already moved to the header level structure and then you are clearing the item level taxes. I hope thats why the changes are not reflected in header level.
Regards,