Generally it is better to not mix different test types (such as C# coded unit tests) into the same project as those containing .aii tests that you want to share between both editions of Test Studio. But it is not impossible either. Note that the list of referenced dll's (along with most project settings) is kept separate between the Dev Edition and the QA Edition. We use the Visual Studio method for storing project settings in the Dev Edition and use our own method for the QA Edition. Test Lists will not carry over between the two editions.
To make your project compile in the QA edition that contains C# coded unit tests, you simply need to add a reference to the required dll for the QA Edition project settings:
C:\Program Files\Microsoft Visual Studio 10.0\Common7\IDE\PublicAssemblies\Microsoft.VisualStudio.QualityTools.UnitTestFramework.dll
See the attached screen shot. It shows adding the Telerik dll's which doesn't apply in your case. But the same method is used to add any other dll references needed. Click on Show Settings from the Project Tab to get to this Settings dialog.
the Telerik team