This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
If you want validation to occur under one circumstance and not another, I'd suggest you create two separate action mappaings both pointing to the same Action class, one specifying validate="true" and the other validate="false". In the Action class, you can tell how the action was invoked by calling the getPath method of the ActionMapping instance that is passed into the execute method as a parameter.