Creating a bootable USB

rEFIt is a useful utility for selecting boot partitions that don't necessarily show up normally (Linux bootloaders, incomplete installs for example, or if there is something out of sync with the boot sectors).

You could use it here to see if it can recognise your USB stick, you could also use it to boot Windows from FireWire if that's at all useful.

You'll need a second usb stick to run it in 'live boot' mode, if you don't want to have it installed on your system, but it's pretty small so even 20MB is enough. Download the disk image and use Disk Utility to clone it onto your second usb stick, then boot with option held and it will appear.

I attach answer here as you guys suggested.

SOLVED - Bootcamp Windows 7 installation without USB, ODD

OK, I'll explain how I worked it. I followed almost of all of David's method here and here, but there are little differences.

Before we start, please note that I'm using MacPro4,1 which does not support USB installation of boot camp and I detached ODD. Instead, I attached another HDD in Bay 2.

1. You need rEFInd, VirtualBox, NTFS support for OS X (like Paragon or NTFS-3G), a bootable Windows installation ISO. Service Pack applied ISO is also ok.
2. Update Mac firmware as recent one as possible. here
3. Open Boot Camp Assistant and download driver files into any usb. (Just 2nd option of 3 of boot camp. if your boot camp assistant does not have 3 options, it would be 1st option)
4. install NTFS support for OS X, rEFInd and VirtualBox.
5. Format a partition with MS-DOS(FAT) which is going to install Windows.
   • I recommend you not to use Boot Camp Assistant app to format. Use Disk Utility instead.
6. In terminal, type diskutil list and remember disk and partition number of target partition. In this example, I use disk 1 and partition 1. So, disk1s1

7. Unmount partition and set permission.

   diskutil unmount /dev/disk1s1
   
   sudo chmod 777 /dev/disk1s1
   

8. Create VirtualBox image with raw disk access. anywhere except bootcamp partition

   sudo vboxmanage internalcommands createrawvmdk -filename bootcamp.vmdk -rawdisk /dev/disk1 -partitions 1
   
   sudo chown $USER bootcamp*.vmdk
   

9. Open VirtualBox and create a VM. Just set disk as what you already made, and ISO file of windows installation.
10. Start VM and install as normally, BUT when you get in 'setting computer name' phase, shutdown VM forcibly.

11. Turn off VirtualBox, and delete all files in the boot camp partition (including BOOT folder and bootmgr file - If you can not find them in Finder, use terminal to delete them or change Finder option with defaults write com.apple.Finder AppleShowAllFiles YES)

    Of course, Before open finder, mount partition first. (If you didn't installed NTFS support, you can't mount or delete file)

    diskutil mount /dev/disk1s1
    

12. double click windows ISO and copy all of the item into boot camp partition
13. Reboot Mac and in rEFInd bootloader, select 'Windows NTFS volume'
14. Install windows again, but DO NOT format boot camp partition.
15. Installation is finished. When you see desktop, install Boot Camp Driver which you downloaded at Step 3
16. After boot camp driver is installed & if you can see 'Windows' on OS X boot loader (which you can enter by pressing alt/option), you don't need rEFInd anymore. You can delete it in OS X.
17. You will see bootup selection between 'Windows 7' and 'Windows Setup' when booting Windows. If you don't want to see it, Go to Control Panel - System - Advanced Settings - Advanced tab - Click Setting button which lies on 'Startup and Restore' section - Uncheck first one.