If I remember correctly a TM backup drive has to be formatted Mac Extended (Journaled) and since it has to be that format it can not be seen or read on a Windows PC. So you will never get that drive to show as a TM backup spot when it is connected to a Windows PC. The only way to have a drive on a network that will show as a TM backup drive is to have it attached directly to the network, A NAS (Network Attached Storage) and then it is reported that most all of those don't work correctly except if it is a Apple branded NAS system like a Apple Time Capsule.
In any event doing TM backups to a NAS system is slow and the big problem comes when, Not If, you need to use it to Restore your system.
Your best bet it to have a dedicated external drive for TM backups only, no other use, and connect it directly to your Mac to do the backups.
Good Luck and Best Wishes.
I do not beleive I installed anything special on that build. It is a windows 7 PC and it does have ACHI enabled cause I also have a HDD inside the WIN7 desktop that has lion on it. It is a hackintosh. I have always been able to see the OSX partition.
I dont see why having Time Machine backing up over the network would be much different then plugging it directly in. I just need the drive to show up in the Time Machine Choice...
I am going to try again. I dont suppose you saw this...