baseline mid 2011 21,5" iMac bootcamp not working

I need help,

I've been trying to install win7 on my iMac for days,

so i'ill start with what i have:

- 16gb flashdrive

-win7-64bit ISO

-Mavericks installed

imac mid 2011, Quad core i5 2.5GHZ, 500Gb HDD, 12gigs of RAM,

what ive done:

I may have installed refit at some point

installed sucessfully win7 with the exact same ISO and flash drive on my macbookair 2013

restored mavericks a couple of times

enable USB in bootcamp by removing the "Pre" in the info.plist file in the Bootcamp.app folder and used "sudo codesign -fs - /Applications/Utilities/Boot\ Camp\ Assistant.app" in terminal to make bootcamp work

Every single time bootcamp does his things i can't get my flash drive (with the ISO and the windowssupport folder from Apple ) to get recognize as boot,

I get the "no bootable device insert boot disk and press any key" line, I reboot with the "alt" key pressed and only the MacintoshHD partition along with de restore partition shows up.

more info:

The usb drive is the only thing connected

I restored mavericks and then just did the part with the info.plist file

Please help me,

You folks have a nice one