How to get CRM custom fields into creator?

How to get CRM custom fields into creator?

Hi

I am using "zoho.crm.getRecordById", "zoho.crm.searchRecords" and "zoho.crm.searchRecordsByPDC" in Zoho Creator to access crm entries in "Contacts".
This works fine and gives me the standard response incl. contactid, Last Name, date-modified etc..
However I cannot extract my custom fields, which i have added in my custom crm layout.
Can i change the standard response from crm? How can i access my custom crm fields in Creator?

thanks in advance
Andy