>The C DLL declarations of the two function I need to call are:
>
>CDK_API int decl CDK_DES_Int(CDK_HANDLE h, const CDK_DIRECTION dir, CDK_DATA_PTR key, CDK_DATA_PTR iv = NULL)
>
>CDK_API int decl CDK_DES_Crypt(CDK_HANDLE h, const CDK_DATA_PTR src, CDK_DATA_PTR dest)

I must admit I'm clueless here. From the typedef statement it's still a pointer. The only thing I'd guess at is to try to pass NULL to it. But take that a face value, it's purely a guess.