You can't install Windows in Boot Camp by mounting a ISO file. With this, the only thing you will get will be a black screen in the next startup telling you that there are no bootable volumes and you won't be able to do anything.
What you have to do is to burn the ISO into a DVD by using Disk Utility. Also, OS X can mount ISOs without a third-party application. Simply open the ISO file, and it will appear mounted in the desktop.
Then, insert a blank DVD, open Disk Utility, right-click the Windows ISO in the sidebar and burn it. Finally, open Boot Camp Assistant and follow the steps. Read Apple's steps > http://manuals.info.apple.com/en_US/boot_camp_install-setup_10.8.pdf