Bingo. I took it step by step, and after few tries I realized, that If I use original kit WOFF fonts actually work, after that I realized that my code actually works too, but only if it is run from the file system directly, not trough IIS. Once I realized that some googling led me to answer:
http://www.dirigodev.com/blog/404-errors-in-IIS7-for-embedded-woff-font-files/
Basically under IIS7 you need to configure mime type for WOFF fonts, otherwise IIS does not serve them.