search for child records with missing link

I have a custom record that is a child record of a transaction.   So there is a field of type list/record that links to the transaction.

However, sometimes the custom record will exist with no transaction. 

I want to be able to search for all the child records that have no associated transaction.  Any idea how to do this?

This doesn't work:

     var filt = new Array();       filt.push(new nlobjSearchFilter(               'custrecord_sea_hu_wo', null, 'noneof', ['0']));              var col = new Array();       col.push(new nlobjSearchColumn('name'));       col.push(new nlobjSearchColumn('custrecord_sea_itemref'));       col.push(new nlobjSearchColumn('custrecord_sea_hunit_qty'));       col.push(new nlobjSearchColumn('custrecord_sea_hu_wo'));       var results =  nlapiSearchRecord('customrecord_sea_hunit', null, filt, col);