Hi there,
I think the simplest way to incorporate a VC++ program into LabVIEW code is by compiling your VC++ code into a DLL. If you are familiar with DLLs, you know that you can export functions from it (functions that other modules can see and call). LabVIEW has the capability of calling functions inside DLLs through the "call library node.vi". This has nothing to do with ActiveX though. And if it's a simple as returning numbers, I'd suggest to stay away from ActiveX.
Let me know if you need more info on DLLs.
Regards,
Azucena Perez
National Instruments