git on UNC path
First open a windows console, Run->cmd
pushd \\172.158.1.254\network_usb
now you should be able to 'cd' through all the directories on the drive. Optionally you can type a git init --bare nameOfnewRepo.git
somewhere.
popd
Now open git bash and cd to the location where you want to clone the repo on the network drive
git clone //172.158.1.254/network_usb/pathto/nameOfnewRepo.git
Note that in git bash the slashes are forward and in the windows console backward.