getSearchRecordsByPDC (ZC - CRM linking via API )

Hi,

Is the getSearchRecordsByPDC restricted only to thedefault predefined colums listed here?

The reason why I am asking this is,

I tried to get the records from Products Module, where the Product category == "Handset".

http://crm.zoho.com/crm/private/xml/Products/getSearchRecordsByPDC?apikey=APIKEY&ticket=TICKETVAL&searchColumn=productcategory&searchValue=Handset

This continues to give me "invalid search colum"

My API KEY and TICKET is working good.
I am able to get the list of contact names / accounts / products into the ZC's drop down box

Please advice
Best Regards
-Deepa Govind