Badi/exit to update tax-code (item level) while posting self-invoice through T-Code MRRL

Hello,

I am looking for a BADI/Exit through which I can update the tax code of line items when self invoicing of credit notes are done through T-Code MRRL. I need a badi/exit where the following information would be available - RBKP-BUKRS, RBKP-XRECH, RBKP-BELNR, RBKP-GJAHR (and if possible RSEG-WERKS). I would need to update MWSKZ at item level.I checked EXIT_SAPLMRMH_002. But it doesnot let us change MWSKZ. I also checked implementation of Badi MRM_ERS_IDAT_MODIFY. But it does not get triggered. Please help. This is urgent. Points will be rewareded to correct/useful answers. Thank you in advance.