Question about redirection

I'm using WARedirect response with static urls, and that works fine. 
What I would like to do is redirect to another seaside app on the same 
server and can't figure out how to get the host/port/prefix so that if 
I deploy the applications on a different machine and change ports, etc. 
I won't have to change the app.
Anyone doing that or have any pointers for me?

Thanks!

Brian