1) Make sure your Windows 8 HD Drive is set to first boot. ( not in your case)
2) Install EasyBCD, http://neosmart.net/EasyBCD/]EasyBCD[/b]
3) Add your second OS.
4) Test both OS's are booting OK.
NOTE: EasyBCD will use the Windows 7 Boot Loader.
After you have made the dual boot with EasyECD, If you would like to use the Windows 8 Boot Loader, do a
Refresh Windows 8
After doing a refresh, you will be using the Windows 8 Boot Loader.
Refresh will also delete EasyBCD.
Refresh may delete other app aswell.