Since all codes in Git can build, don't overwrite them with files from VSS if you want a stable testing environment.
If you do need a later version, take care to download the minimum from VSS, and you can always go back with "git reset --hard" which means drop all local changes. Before downloading new code from VSS, remember to commit your local modification to a branch, and switch to "master" to do the test build. Once build is done, then switch back and rebase the branch. The "master" branch is used to track upstream.
When you are going to commit to VSS, first do a rebase, then make sure it works, then merge it to "master" and (optionally) delete the branch. Finally, commit to VSS. In this way the history can be retained by the merge.
I sent this email today, donno if this is the right way (TM) to use Git. But we must do it. Try it first.