WCF Does Not Select Web Transformation When Building the Project

This problem is related to WCF Web.Configuration Transformation - How to Write?.

I created the web transformation file, pre-viewed it and it showed the correct changes. Then, I set the build active configurations accordingly, built the project, and published the project. The built (*.dll) and the published web.config were still the old one. The transformation did not take effect at all.

Any help out there?