How can I get actual value for SearchColumnSelectCustomField?

I perform a search like (C#):

var search = new ItemSearchAdvanced      {          columns = new ItemSearchRow              {                  basic = new ItemSearchRowBasic                      {                          internalId = new[] { new SearchColumnSelectField() },                          itemId = new[] { new SearchColumnStringField() },                          customFieldList = new SearchColumnCustomField[]                              {                                  <strong>new SearchColumnSelectCustomField                                      {                                          internalId = "custitem_item_category"                                      }</strong>                              }                      }              }      };    var response = _service.search(search);

and here is a piece of received XML:

&amp;lt;platformCore:searchRow xsi:type="listAcct:ItemSearchRow" xmlns:listAcct="urn:accounting_2010_2.lists.webservices.netsuite.com"&amp;gt;      &amp;lt;listAcct:basic xmlns:platformCommon="urn:common_2010_2.platform.webservices.netsuite.com"&amp;gt;          ...          &amp;lt;platformCommon:customFieldList&amp;gt;              <strong>&amp;lt;platformCore:customField internalId="custitem_item_category" xsi:type="platformCore:SearchColumnSelectCustomField"&amp;gt;                  &amp;lt;platformCore:searchValue internalId="10" typeId="104"/&amp;gt;                  &amp;lt;platformCore:customLabel&amp;gt;Category&amp;lt;/platformCore:customLabel&amp;gt;              &amp;lt;/platformCore:customField&amp;gt;</strong>          &amp;lt;/platformCommon:customFieldList&amp;gt;      &amp;lt;/listAcct:basic&amp;gt;  &amp;lt;/platformCore:searchRow&amp;gt;