I've done it on my Mac Pro. Your mileage may vary, but this is how I did it:
Opened Disk Utility
Clicked on the name of the drive (in my case, 1 TB TOSHIBA)
Went to Partition
Clicked the "+" button near the bottom left
Added 2 partitions
Kept the partition scheme as GUID
Changed the format from "Mac OS Extended (Journaled)" to ExFAT
Restarted the computer with the Windows disc in the CD drive while holding down the Option key
Selected the CD named "Windows"
Booted straight into the installer
Of course, before I did that I download the Windows drivers from Apple's site.
The only downside is whenever I boot into Windows, it asks me which I want to boot. The best way is to use System Prefs on the Mac to select to boot from the Windows partition (SP will only show 1 unified Win Partition). It will always ask, however it defaults to Win 8. If I want to boot Win 7, I have to select it from the menu Win 8 pulls up during boot. The computer then has to reboot and if I didn't use Sys Prefs, I have to hold the Option key back down and select the Windows partition.
Also, if you do this, you have to install Windows 7 first. This sets up the BIOS emulator. If you install 8 first, it might not work due to EFI.
This is a pretty old post (2014) and as such, windows 10 did not yet exist. Also I recommend you do not bump old threads as it may be against the rules. (not sure but just a guess) Anyways my problem has been solved for a while.