I'm afraid not. You would need to create an intermediate library written in a .NET language. Then B4PPC could call that .NET library which could in turn use functionality not imlemented in B4PPC to call your native library.
A "DLLWrapper" will be a good thing to do that, if someone can make it, it can be very useful.
If you mean a generic wrapper that could access any native dll then I don't think that is possible. It would have to be written specially for a particular dll.