Flex DataGridColumn ID missing?

I am dynamically creating a Datagrid in AS3. In MXML, it is permissible to write:

mx:DataGridColumn dataField="abc" id="testColumn"

      

        
        
        
      

    

in AS3, however I cannot use the id property, it was not found. Any ideas?

var dgc : DataGridColumn = new DataGridColumn();
dgc.id = "testColumn"; (NOT WORKING)

      

        
        
        
      

    

Thanks Martin