如何控制.Net在名称空间冲突中选择哪一个程序集?

I need to (bear with me) for some reason or another use the WinRT version of the System.Text.Encoding namespace. I can add a reference to the assembly manually and such, but it will still use mscorlib's implementation. And I can't completely remove mscorlib apparently. I need to (bear with me) for some reason or ano