Force installer to fail when ports are not available?
===

I am using install4j to install an intranet application which requires an HTTP and HTTPS port.  I would like to test that these ports are available and warn the user/block the installation until they select unavailable ports.  

The only avenue I see for this (besides custom code) is to ensure the windows service fails if the application cannot bind to needed ports, and use a Failure Strategy "Ask user whether to retry or quit on failure".  In the web server startup code, I use System.exit(1) if the server cannot bind to ports.  However, this does not appear to register as a failure to the installer - the installation proceeds without invoking the failure strategy.

What is the proper approach for signaling failure to the "Start a service" action?  Have other people taken an alternate approach to guaranteeing the installation uses available ports?
