I tried out the demo and created an installer, and was impressed that it actually worked on Windows 8.1 and that I was able to build the installer on an Ubuntu server. However, I noticed that installjammer is no longer supported.
Have you considered integrating with nsis instead? As of December 24th, 2013, they are still actively working on that project. Like installjammer, developers can create installers from Linux that target Windows platforms.
Thanks for creating this tool!