OK Phillo, I jumped into this one thinking you would want to marshal the unmanaged array into the managed code, using c#.
This is out of my scope. In doing a quick search, as I am sure you have done, I notice that even when people manage to successfully interop a managed C# dll from a C++ module, they also get stuck on the issue of passing a byte array into managed code.
Here is one thread in this forum that might help:
Using array allocated in native dll but here is my suggestion:
1. Post your question in the C++ forum.
2. If still no answer, post in this forum again. Hopefully, the moderator will acknowledge that I was of no help here and since no one else has jumped in, a new thread is acceptable.