Add field to create-ticket form

[Peter, U]

I'd like to add a field to standard portal : requested_for
i tried to follow the tutorial witout success. Whole twig redefine.
And also I checked the custom_field extension (for servicesubcategory) the result was the same (the field does not show in the form)
the code

 <?xml version="1.0" encoding="UTF-8"?>
 <itop_design xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.6">
   <module_design id="itop-portal" _delta="must_exist">
    <forms>
         <form id="ticket-create" _delta="must_exist">
       <twig>
    <div class="form_field" data-field-id="requested_for">
    </div>
 </twig>
  </form>
  </forms>
 </module_design>
 </itop_design>

in the module definiton i put the
1st time: 'itop-portal-base/2.0.0'
2nd time 'itop-ticket/3.2.1'

how can I achive this?
Thank you in advance

[Jeffrey Bostoen]

You'll need to redefine (check _delta="redefine") the entire twig presentation.