title: Servicenow - Service Catalog Reference Field - Insert different column than the display value
body: <p>Let me describe my problem:
  I have a table for all my IT-Services. I reference to this table more than once, for different purposes. Most of the time I need to reference to the name of the service. That's why I keep the name as displayed value. 
  One Column of that table is a service_id (custom field) which is for example "Service_004". Now in a catalog request Item the User has to fill in the service_id in a reference field. 
  But since I have the name as displayed value, and I need it in other forms, I am unable to reference to the service_id.</p>
  
  <p>Using the variable attributes field I managed to let the service be found using the autocomplete function. But in the reference field I still get the servicename. I know that I can change the display value in the dictionary, but this breaks other functions. So what I need is to change the display value just for one reference field. </p>
  
  <p>Also I tried to create a new table called IT-Services2 with reference to my table IT-Services. Then I switched the display to true in the new table for my service_id, but this will even change it in the parent table. </p>