Customer Master using Appended structure KNA1

Hi

We have to update few ZZ description fields in ZAKNA1, which are not part of user interface in XD01/02/03. The available options are such as LSMW, Batch input require code addition through user exit ZXF04U01/ EXIT_SAPMF02D_001.

I would like to use BAPI as we have a plan to use web services. Any idea how to extend the BAPI's such as BAPI_CUSTOMER_CHANGEFROMDATA1 or BAPI_CUSTOMER_CREATEFROMDATA1 using best practice? I donu2019t find any extension structures like other BAPIu2019s have. Without ExtensionIn and ExtensionOut parameters, a BAPI can not be enhanced correct?

The version we are using is ECC 5.0. Any ideas with customer master BAPI will be greatly appreciated.

Bala