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 Micheal 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 2

Disk 2 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


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