I know this question is old but it is still valid. I was never able to write a Mac installer image to my Flash Drive and have it bootable, unless I did it on a Mac. Using Michael D. M. Dryden's [Link][1], I was able to use the Diskpart command to clean and prep a GPT partition on a flash drive for an OSX Mavericks install image.

I used TransMac on Windows 7 to restore the image file I had to the Flash Drive, it created a bootable Mac image on my flash drive. Someone had reported that the method for using DISKPART did not work, but I have done this twice and it works remarkably well, and it's the only method I could find to create a Mac-Bootable Flash. I've been trying to post this to confirm that it works for some time, I just hope it helps someone else, because it is a very easy solution.

Here are the Diskpart commands used to prep the Flash Drive, just to have them here in case my Link does not work:

diskpart

DISKPART> list disk

(Find the disk number)

DISKPART> select disk x (from result of List Disk)

Disk x is now the selected disk.

DISKPART> clean

DiskPart succeeded in cleaning the disk.

DISKPART> convert gpt

DiskPart successfully converted the selected disk to GPT format.

DISKPART> create partition primary

Note: I use "Rufus" for all other USB writing and formatting for Windows systems, it's a great app, but I had previously tried to format the drive as GPT using that, as a Fat32 partition. When I tried to inject the image, Transmac told me that the drive was "write protected". So basically, the USB drive cannot have any high level formatting, the Windows system should detect the drive as "not formatted" for this to work, which it will if prepped right with Diskpart.


  [1]: http://superuser.com/questions/383235/create-a-bootable-usb-drive-from-a-dmg-file-on-windows