We can convert Windows 8 / Windows Server 2012 ISO into Bootable USB. First thing, we need to have the ISO. Then please download Windows 7 USB/DVD Download Tool:

http://www.microsoftstore.com/store/msusa/html/pbPage.Help_Win7_usbdvd_dwnTool

Install the software and open it. Then, prepare USB 8 GB at least and make sure to format using FAT32. This is important, since UEFI only boot FAT32 format.

Then all you need is import the ISO and click Next button!