COM server written in C#

Below is the partial code for COM server written in C#. I have copied an interface.

COM server interface in C#:

[Guid("4df99b70-e148-4432-b004-4c9eeb535a5e")]
public interface IFunctionDiscovery
{
unsafe void GetInstanceCollection(string pszCategory, string pszSubCategory, int fIncludeAllSubCategories, CFunctionInstanceCollection** ppCFunctionInstanceCollection);

};
public class SampleClass : IFunctionDiscovery
{
public unsafe void GetInstanceCollection(string pszCategory, string pszSubCategory, int fIncludeAllSubCategories, CFunctionInstanceCollection** ppCFunctionInstanceCollection)
{
System.Console.WriteLine("GetInstanceCollection() called...");
CFunctionInstanceCollection* ppFIC = new CFunctionInstanceCollection();
ppCFunctionInstanceCollection = &ppFIC;
}
}


Compiling the C# code, gives an error:

Program.cs(19,21): error CS0208: Cannot take the address of, get the size of, or
declare a pointer to a managed type

Compiler is pointing at the last argument in GetInstanceCollection method of COM server. Does anyone know how to fix the problem?

Thanks!