Guillermo,
I've created a quick video showing how we use Dolphin with Microsoft
Visual SourceSafe. You should be able to perform similar steps with
other file-based SCCSs like Git etc. Indeed, I would expect that you can
avoid having to perform the "version label hack" mentioned in the video
(necessary because of a deficiency in SourceSafe).
Unfortunately, we don't have any direct experience of alternative
systems so I can't give any explicit advice on anything other than
SourceSafe. Maybe other users will be able to share their experiences
(if any).
You can find the video here (
http://bit.ly/externalsccs) or in the
Object Arts video library.
Best regards
Andy Bower