Managed C++ classes

Question

I'm attempting to create a managed C++ class from some an already existing application that I have however some of the classes allow private access via the 'friend' keyword and i've heard that this presents a problem when creating managed code. Does anyone know how i could get around this? Is it possible to still create managed code without having to make the classes managed? More specifically, what i'm trying to do is make the methods of an API, that allows the playback of audio through kernel streaming, that has been written by Microsoft accessible through C#. The application that has been developed using the API is available here: http://www.microsoft.com/whdc/hwdev/tech/audio/DirectKS.mspx My plan has been to export classes used in the API written in C++ into a managed dll, however, as I have described previously, I am now having problems with this approach. Does anyone know of any other way in which this problem could be dealt with? Cheers very much for any help, Richard.