you don't,you have to wait for a mod, but until then, i will tell you that it is possible, but you have to drill and tap new holes for the mobo standoff and also you have to cut holes for all the usb, printer, keyboard and mouse ports and everything else
It can be done but then again, I could also have my computer powered with a dozen mice in running wheels.
It's a hell of alot work and alot of measuring. I would just buy a new case, but then again, I am kinda lazy, and i hate math and tape measures.