It uses the RAM_wb IP for the instruction RAM (With a few bug fixes). This doesn't really provide a way to load a boot rom as far as I can tell but I will worry about that later when *something* works. I've also been fiddling with the VMWare image which involved replacing hard coded IP addresses with opencores.org in three scripts. I'll see later if I can at least update two of them myself. The first is unfortunately embedded in the VMWare image, I may still be able to update it and see about making it also work with VirtualBox.
I am surprised that anyone has ever used this stuff and gotten it to work. No wonder companies are willing to fork out so much money for a solution.