How To Search A Custom Field In Zoho CRM Using API ?

Hi,

I have created some custom fields in zoho crm and wanted to search that custom field value from zoho creator. I have tried using zoho functions such as "zoho.crm.searchRecordsByPDC", "zoho.crm.searchRecords" and also the following API,

http://crm.zoho.com/crm/private/xml/Contacts/getMySearchRecords?loginName=test@test.com&apikey=test&searchWord=test

But all of the above mentioned search functions are accessing only mandatory or system fields of zoho crm and not able to retrieve the custom fields record data.

Is there a way to do a global search or search a record based on the custom field value in zoho crm using the API or any function from zoho creator.

Please let me know if there is any such API or function exist.