Nothing. If a multi-project .sln file is specified in the Filename field, all projects in the solution that are configured to be built in the VS configuration manager (Build | Configuration Manager, Build checkbox column) for the specified solution configuration(s) will be built.
http://www.visualbuild.com/Manual/vs...olutiontab.htm
http://www.kinook.com/Forum/showthre...?threadid=1609