I understand that you can package/deploy a database project from Visual Studio, but, does the database project produce an output that can be deployed using msdeploy, or are they totally unrelated? e.g. msdeploy.exe -deploy mydatabaseproject
Alternatively, maybe the dbproj just outputs scripts that can be included in the 'Package/Publish SQL' tab that will be included in the web deployment package and subsequently executed as part of the web deploy?