Entire Windows Time Machine Network Process
I went through a lot problems mentioned here but I figured it out after reading many posts and articles. Here is a basic breakdown.
1.Create a windows network share from a folder i.e. E:\TimeMachine
2.With Finder open using the CMD+K option enter the share path i.e. smb://machinenamehere/TimeMachine/
3. Open Terminal and run: defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1 * This shows the unsupported network drives.
4. Download
http://cache.gawker.com/assets/images/lifehacker/2010/11/makeimage.sh Script
5. CD to downloads folder where makeimage.sh script is located.
Run script from terminal sh ./makeImage.sh 130 /Volumes/TimeMachine/ where 130 is the size you want, change if you like and TimeMachine is your mounted volume. Press tab twice at /Volumes to get a list of all usable volumes.
6. In finder locate the TimeMachine share and click on the Sparsebundle this will mount Time Machine Backups on your desktop and will make it show up in available volumes.
7. In Terminal run sudo tmutil setdestination "/Volumes/Time Machine Backups/" enter your password and don't forget the quotes.
8. The Back up option will now show when you click on Time Machine and you can select the drive and begin backups.
I hope this helps I spent many hours figuring this out my configuration is Windows 7 and MacBook Pro running OS X 10.8.3