Mandatory steps:
- Add your model to DARequiredROMVersions
- Delete the word "Pre" from UEFIModels and add your model
- Delete the word "Pre" from USBBootSupportedModels and add your model
- Remove your model from Win7OnlyModels (if its there)
The last step is to do a code sign. Boot Camp Assitant will not run if it's been edited. You need to resign it. Open Terminal (use spotlight to find it) and type this:
sudo codesign -fs - /Applications/Utilities/Boot\ Camp\ Assistant.app
Good luck!