Hi Madhukar,
This you can achieve by enhance the method GET_POSSIBLE_FIELDS in your search impl class just debug the method. This method will gives the fields which are there in your search configuration fields.
try to debug then you may come to know..
if you want to hide the filed in the search config
* Adjust search criterion values having drop down listboxes in case central search has been received
me->adjust_search_criteria_values( iv_advanced_search = lr_qs
iv_context = central_search ).
check this method too ADJUST_SELECTION_PARAMS.
thanks & Regards,
Srinivas.