The lack of answers and my fruitless search yields one answer. InstallShield LE is not capable of this.
You are better off using WiX for this. Seeing how other have done this and modifying it is the quickest way to get something up and running.
This is the result of such work: http://halsvik.net/downloads/WebSetup2013Installer.zip
And it seems MS has decided to add support for the old Microsoft Setup projects (VDPROJ) again: http://blogs.msdn.com/b/visualstudio/archive/2014/04/17/visual-studio-installer-projects-extension.aspx https://visualstudiogallery.msdn.microsoft.com/9abe329c-9bba-44a1-be59-0fbf6151054d