We have a Team Build server where I work, and we were having some issues with getting the projects to build due to some issues with your MSBuild task. If used in a web application project, your build process breaks down when looking for the obj\Debug folder. To correct this problem, I added a simple check to your targets file.
Here's the actual error:
C:\Program Files\MSBuild\Devart\v3.5\Devart.Data.Entity.targets(32,5): error : DevartEntityDeploy: Could not find a part of the path 'C:\(REMOVED)\obj\Debug\(REMOVED).ssdl'. [C:\(REMOVED)\(REMOVED).csproj]
And here's the fix:
The part in bold above just checks to ensure the directory exists before calling your DevartEntityDeploy target to generate the ssdl files.