In the SOS GUI client under Tools->Options-> General, there is an option to "Make SOS your default SCC provider." Check that when you want to use SOS for source code control. Uncheck it and VSS will be your SCC provider.
To keep the binding straight when you switch, be sure to open your solution from source code control. This is menu item is in Visual Studio or VS.NET under File->Source Code Control->Open From Source Code Control.
Switching between VSS and SOS as your SCC provider
Moderator: SourceGear
Switching between VSS and SOS as your SCC provider
Linda Bauer
SourceGear
Technical Support Manager
SourceGear
Technical Support Manager