If you go somewhere via a particular place, you go through that place on the way to your destination.
e.g. We drove via Lovech to the old Danube town of Ruse...
e.g. Mr Baker will return home via Britain and France.
If you do something via a particular means or person, you do it by making use of that means or person.
e.g. The technology to allow relief workers to contact the outside world via satellite already exists...
e.g. Translators can now work from home, via electronic mail systems...