Bootcamp will not install windows 7. no bootable device

Have a long winded story here so read through at your own pace.

I have a Mid 2011 iMac 27. Im currently running 10.9 mavericks and at first I could run run the Boot Camp assistant because it would not allow me to create a windows installation. I am using an ISO file (legal). After searching the fourms and a few Terminal commands later I got boot camp to allow me to create an installation USB drive. I first created the drive with my Windows 7 ISO. After my computer restarts it tells me that there is no bootable disk and to press any key to reboot. Searched the forums again and came across the suggestions to user rEFIt to allow me to choose my boot drive. This help very little and still got an error that the boot drive is not readable. I reformatted my internal drive and created the partition again, this time with a Windows 8.1 ISO. I got slightly further with this one. I was able to load the installer and input my CD Key. After it asked me to format the BOOTCAMP partition I cam across an error that stated the drive is partitioned as MBR (Master Boot Record) and that it is not compatible. At this point I was extremely frustrated. Restarted into my Mac OS and the drive was partitioned correctly as NTFS.

At that point I decieded maybe Its just not the right thing to do. I installed VirtualBox and ran the Windows 7 iso with no issue. The installation took maybe 20 mins and I was done.

I spent 5 hours trying to determine the issue with bootcamp. I went to a third party freeware and my issue was resolved in 20 mins. Has anyone had issues with bootcamp simply not reading ISO files when its time to install Windows?

Any suggestions would help.

Thank you!