Comment 34 for bug 1289977

I managed to get it work. Have a look here for the solution: http://stackoverflow.com/questions/23164040/grub-2-cannot-find-efi-for-windows/23164859

You will have to adapt your configuration to reflect your system's setup but I've posted mine so you should have enough to get it work. You will have to downgrade the files mentioned here by another user. Then an additional step is needed to make Windows 8 (in my case work).