JAXB how to drop tag element in xml

From: dsp (sesh74us_at_yahoo.com)
Date: 03/31/04 

Date: 31 Mar 2004 09:30:28 -0800

Am using JAXB to generate the XML file using java objects,..
The java class files were generated using XSD/XML schema.

one of our requirement is to some times completely drop the Element
and not even include it as empty tag <element/) in output XML file

how do i solve this,...?

thanks