This video will show you how to create a bootable Windows 7 8 USB on a Mac.
You can use the bootcamp assistant to create a bootable Windows 7 8 USB on a Mac. However the option may not be highlighted in your bootcamp assistant.
To make the option appear you can try the following steps.
Step 1. Click on Go then Utilities. Find the Bootcamp assistant, right click on it and go to Show package contents and then go into the contents folder.
Step 2.Copy the info.plist file to the desktop and make a backup copy of it and open it.
Step 3. Find the line which says PreUSBbootsupportmodels and remove the Pre from the line. Try running the bootcamp assistant again and this time you should have the Create a Windows 7 or later install disc option.
Step 4 Copy the info.plist back to the contents directory. And start the bootcamp assistant again and see if the Create Bootable USB Drive for Windows installation comes up. If not try this next step.
Step 5 Change the USBbootsupportedmodels in the info.plist file.
You can find the model on the Mac that you are using by going into the Apple menu then click on About This Mac and then click on More info. Next click on System report and under Hardware Overview look up Model Identifier.
In the example in the video my MacBook model was MacBook7,1.
In the info.plist file I had to change the USB supported models to my MacBook model so that I could create a Windows USB on a Mac.
Hope this works guys. Feel free to leave some feedback.
For more into you can check out Apples discussions page here.