title: User input in Z fields is not processed in CUSTOMER_ADD_DATA BAdI
body: <p>I need to know what to process (save &amp; display) with user input in custom fields.</p>
  
  <p>My Setup: <br>
  - new subscreens for Transactions XD.. (e.g. XD02)<br>
  - Using badi customer_add_data and customer_add_data_cs<br>
  - added some custom fields to tables, e.g. KNA1<br>
  - created function Group with dynpros for Transactions XD..<br>
  - new customer fields are displayed in XD..<br></p>
  
  <p>However, nothing I enter into my new fields seems to be processed. I dont know how to continue my implementation. </p>
  
  <p>What I tried in the BADI:</p>
  
  <pre><code>" wokrs, saves data input 
  method IF_EX_CUSTOMER_ADD_DATA_CS~GET_DATA.
  
    "SAPLZSD_FOO_CUSTOMER = my function group
    CONSTANTS: c_foo(50)  VALUE '(SAPLZSD_FOO_CUSTOMER)KNA1-ZZFOO'. 
  
    FIELD-symbols: &lt;fs&gt; TYPE ANY.
    ASSIGN (c_foo) TO &lt;fs&gt;.
    IF sy-subrc = 0.
      s_kna1-ZZFOO = &lt;fs&gt;.
    ENDIF.
  endmethod.
  </code></pre>
  
  <p>What I tried in the PBO to display the custom field value</p>
  
  <pre><code> " does not work, stored values are not display in dynpro
   MODULE status_2001 OUTPUT.
  
    DATA: gf_eori TYPE kna1-zzeori.
  
    CONSTANTS: c_foo(34)  VALUE '(SAPMF02D)KNA1-ZZfoo'.
  
    FIELD-SYMBOLS: &lt;fs&gt;.
  
    ASSIGN (c_foo) TO &lt;fs&gt;.
    IF sy-subrc = 0.
      kna1-zzfoo = &lt;fs&gt;.
    ENDIF.
  ENDMODULE. 
  </code></pre>
  
  <p>What Interface methods of  customer_add_data and customer_add_data_cs do I have to  use? What has to be written into the PBO/PAI of my dynpros? </p>
  
  <p>How could a solution look, if the new fields are for example: knvv-zfoo &amp; knvv-zbar.</p>
  
  <p>I am new to customizing SAP and Need some quides in General how to use BADIs.</p>