C++ and C# Solution builds locally (VS2012), but not on TeamCity (MSBuild)

So I have a solution that contains a C# project which references a dll that a C++ project in the same solution builds first.

The C++ project is strongly named, and the C# is marked to be signed. The final dll produced is used in another project that is to be signed as well.

Here is the issue I have. Locally in VS2012, the solution builds with no errors. When I commit and a build gets triggered on TeamCity the build fails and I get the following error:

[Csc] CSC error CS1577: Assembly generation failed -- Referenced assembly 'Zodiac.Cmt.Imaging.Etc1' does not have a strong name.

I used sn.exe -vf to check if the outputted dll is valid and strong named from the C++ project and it reports that it is valid.

At this point I am lost as to how to fix this.

Thanks in advance for your help.