While it is not suggested, you can uninstall IIS by remote desktoping into your WHS, and then use the Add/Remove Windows Components tool to explicitly remove it...
Start -> Control Panel -> Add or Remove Programs -> Add/Remove Windows Components -> Application Server
Once there simply uncheck the IIS box and hit OK and then Next.
Rather than outright removing it though... I sense that you want to let Kerio Mail Server have port 80 to itself... so instead it’d be easier to just tell IIS not to use it... to do that follow this path...
Start -> All Programs -> Administrative Tools -> Computer Management -> Services and Applications -> Internet Information Services (IIS) Manager -> Web Sites -> Default Web Site
Once there, right click on the Default Web Site and choose Properties, next enter a new port number for the TCP port, something that is not likely to be used.
By following this second path, you let Kerio have port 80, but you still can use access your home servers remote access site over ssl, you just have to remember to browse it with https instead of http.
Is this what you are looking for?
