How to make TC5.0 recognize MSBuild compilation errors?

I have a .NET project with a Rake build script. Rake calls msbuild.exe to do the actual compilation. When I configure a TC 5.0 build (using the Rake runner), compilation errors are not recognized as such by TC.  When a compilation error occurs:

1. The build does abort and is flagged as a failure;
2. The log overview does not contain the compilation error message. I have to go to Build Log -> All Messages to see the failure;
3. The compilation failure is not reported via email. The {COMPILATION_ERRORS} placeholder in my email notification template is replaced with a blank string.

What do I have to do to get TC to recognize the compilation errors?

Thanks in advance,
Seth Petry-Johnson