It sounds like you have hidden values on the form submitted with confirm.jsp and you want to send them to the server at 188.8.131.52. You can't. You're options are to submit them in the URL as a GET or have the user submit another form and use a POST. Let's look at the flow as to why:
1) User submits confirm.jsp
2) Hidden parameters are in the HttpServletRequest to your server
3) You do stuff on your server
4) Struts forwards to the other server
5) The user sees the aspx page on the other server
Since the aspx page is on another server, it doesn't have access to your HttpServletRequest.