If you are working with a source control application other than those directly supported in Flare (i.e., Microsoft Visual SourceSafe, Microsoft Team Foundation Server, Apache Subversion), you can use the Microsoft Source Code Control API (SCC API) to integrate that application with your Flare project.
The SCC API is an interface specification defined by Microsoft that defines the interface between an application (in this case, Flare) and a source control provider (e.g., Perforce, CVS), providing hooks for a number of common source control operations (such as check out, check in, get latest, and so on).
Many source control providers adhere to this interface as a standard for source control integration, including (but not limited to) the following:
If you are using a source control package that supports the Microsoft SCC API, install the plug-in that is provided by that tool and follow any included instructions. This plug-in from your source control provider should be installed on the client machine (i.e., the computer that is running Flare). Once you have done this correctly, you should be able to select that plug-in from the Flare interface whenever you are asked to select a source control provider (e.g., when binding a project to source control).
Note: It is not mandatory that you use the SCC API to use a source control application for your Flare project files. It is only necessary if you want to take advantage of the source control integration features inside Flare. Otherwise, you can manually add your Flare project files to any source control application.