It makes a lot of sense to write the ServerResourse for Hyper-V in C#, because there's a lot of frameworks written in the Microsoft ecosystem with C# in mind.
If that's the case, then it also makes sense to use the Microsoft compiler to compile the ServerResource. I'm unclear how this impacts contributing the code to Apache CloudStack. In particular: 1. Does dependence on the Microsoft compiler mean that the source end up in the non-OSS build? 2. Is the plugin able to participate in the BVT?