We have a small remote office that often share data with us. I learned that the data is shared as a email attachment, but that obviously leads to versioning hell and overriding.

I am looking for a way for then to synchronize a folder directly on our main office domain controller.

I personally use LiveMesh, but I would like a tool that is synchronized to our server directly without a 3rd party hosting the data, since we already have an online backup service taking care of the offsite backup.

What enterprise class tool would let us synchronize a folder from a remote computer that is out of our domain, into our the file server of our domain? The synchronization has to be two-way, e.g.: Someone from the remote office will create an invoice. Someone from our office will review it and make modification to it. The remote office need to see the change.

Our server is on Windows 2003.