I"ve try to found it in my archive, but have noting to promise.
The engine was totaly rewritten by me for the VKB rudder controller and old code for general HID controller sinked in history due misinteresting, sorry :-(

PS. I"m extremely recommending to look at freeware ObDev AVR USB software stack for new projects. The boys make exclusive work to adopt original Igor"s ideas for general purpouse C-based projects. They have some hid-controlers examples too.